Swimming Pool Stains Removal Guide

swimming pool stains removal

A stained pool can be beyond embarrassing. Sometimes it’s even worse than tattered carpet and stained couch cushions. The negative aesthetic can put a damper on your entire backyard experience. Unfortunately, hard-to-remove pool spots and stains will take a bit more than just brushing to remove. You need some powerful methods and techniques to treat existing stains and prevent future pool stains. But how?!

Don’t worry, we’ve got you! In this post, we’ll go over the different causes of pool stains, how to identify and treat different types of stains, and finally, how to manage a pool that stays stain-free.

What Causes Pool Stains?

Stains on pool surfaces can happen from a number of different scenarios. Most often, poor water balance and insufficient cleaning habits are to blame. But sometimes, the quality of your water source or even the construction of the pool can cause issues. The first step in getting rid of the stained eyesore in your pool is to diagnose the stain type. With this information, you can better identify the cause of the stain and start devising a treatment plan. Swimming pool stains are most often caused by:

  • Metals or minerals in pool water coming out of solution
  • Rust emerging through the wall, floor, or around fittings
  • Organic material like leaves, dirt, oils, worms, or algae

Pool Stain Identification

How do you know which is which? First of all, determine if the stain is organic or metallic. The biggest clues involve the stain color, location, and general appearance of the stain (streaky, splotchy, evenly distributed, etc.).

In some cases, a pool may appear stained when it’s really just algae. If the stain brushes off even slightly, or if the discoloration responds to shocking the water or sprinkling granular chlorine over it, then you’re most likely dealing with an organic stain or an algae bloom. Visit our Pool Info page for more information on how to treat pool algae, or keep reading below to learn more about organic stains.

Jack's Magic Stain ID Kit

If algae and other organic contaminants aren’t the cause, it is probably a stain caused by metals or minerals. You may need further identification. In this case, something like Jack’s Magic Stain ID Kit can help determine the exact type of stain you have. The stain’s reaction to any of the four topical tests will indicate the necessary product for its removal.

Another type of “stain” we get questions about involves natural mottling in plaster. This isn’t actually a stain. Rather, it’s a natural effect often seen in plaster pools due to natural product variations in hue and shade as the plaster is applied. Mottling is often subtle, but cannot be removed.

Metal or Mineral Pool Stains

An important part of pool management is testing and balancing your pool water. Test for metals and calcium content, and properly balance all aspects of water chemistry. When water is unbalanced, metals and calcium in the water can fall out of solution. This causes stains and scale to appear on pool surfaces. Maintain proper water chemistry and use stain and scale chemicals to manage metals and help prevent these types of stains from happening in the first place. Here’s a quick summary of the causes and colors of different metallic or mineral-based pool stains:

Cause of StainCommon Causes/SourcesCommon Colors
CalciumPlaster, Grout, Mortar, Cal-Hypo Shock, Hard Water SourcesWhite or Light Gray (Crystals or Precipitate)
CobaltFiberglass Pool ShellsDark Gray, Black
CopperCopper Algaecides, Ionizers, Corrosion of Copper Pipes/Fittings/HeatersDeep Blue, Blue-Green, Green, Teal; Sometimes Reddish-Brown, Yellow-Brown, Black, or Purple
IronWell Water, Corrosion of Iron Pipes/Fittings/RebarDark Red/Orange, Brown, Black; Sometimes Pale Green or Blue-Gray
ManganeseWell WaterPink, Rose, Purple, Black, Green
NickelCorrosion of Nickel-Coated Nuts/Bolts/HeatersGreen, Brown, Black

Scaly Buildup

A mineral or calcium stain is typically a scale, dirt, and oil film, presenting as dull discoloration. It’s most often found at the waterline in scaly white, gray, or tan deposits. But in certain water conditions, scale can deposit an all-over dirty film onto other pool surfaces.

In the Swim's super tile and vinyl cleaner

Manage excess calcium and minerals in pool water with In The Swim Stain Away, Natural Chemistry Scale Free, or Jack’s Blue Stuff. Using enzymes like Pool Perfect or Pool Magic can break down oily organics, preventing them from taking over your pool and compounding the problem. For cleaning tile or vinyl at the waterline, try using our Super Tile & Vinyl Cleaner spray before resorting to more drastic measures like a professional acid wash or bead blasting. Inground concrete pools can also use pumice stones to remove scale buildup and efflorescence from tile, grout, plaster, PebbleTec, and stonework of all types. Unfortunately, pumice stones are not an option for vinyl liner pools.

Metals in the Pool

If the stain looks like rust, it probably is. Metal objects mysteriously finding their way into the pool typically cause isolated spots of rust stains. Either that, or the rust is coming from the inside-out. On concrete pools, this sometimes happens when rebar tie wires are too close to the surface, or if a crack allows water to reach the rebar steel. On vinyl pools, galvanized steel walls in wet soils can eventually break down and start staining the liner. In this case, the process can be slowed with paint and wall foam.

If your water test indicates that your water has metals in it, the first thing to do is to manage and control those metals with a powerful stain fighter like In The Swim Stain Away, Metal Free, Metal Klear, or CuLator. Using these treatments regularly will not only help address your current stain situation, but will help maintain protection and keep metal stains from returning in the future.

Treatment and Removal of Metal/Mineral Stains

Depending on the type of metal stain you’re dealing with, there are a few different ways to go about removing it. A common treatment is to use something like Natural Chemistry Stain Free or our own A+ Stain Remover, both of which are made of ascorbic acid. These products are basically granular Vitamin C, making them a great all-natural pool stain remover. To know if it will work on your pool stains, take a Vitamin C tablet from your medicine cabinet, and either grind it up and sprinkle it, or rub it against the stained area to see if it lightens.

a+ stain remover

If that doesn’t work, you may want to try something like our EZ Stain Remover instead, which is tough on metallic stains in any type of pool – concrete or vinyl. For severe staining in pools with very high metal levels, or for pools that have had chronic staining problems for many years, re-treatment may be needed. However, for most pools with light overall staining or a few spots here and there, EZ Stain Remover will often do the job.

If the staining has reached your pool steps and they need an extra scrub, try Jack’s Magic Step Stuff to whiten your pool steps back to like-new condition. Step Stuff is a two-step process that restores stained ABS plastic vinyl liner pool steps. Remember to follow instructions and water balance guidelines carefully for best results.

For extremely difficult stains in plaster pools, or to address scale buildup along the waterline, you can also try lowering the water level and applying a weak solution of Acid Magic directly to the wall from a watering can. Acid Magic is a user-friendly alternative to muriatic acid. Start by pouring two cups of Acid Magic into one gallon of water. Then apply this mixture directly on plaster or pebble surfaces, and hose off thoroughly according to product label instructions. If the staining is severe enough or covers a majority of the pool, you might be ahead to look into professional acid washing services, instead.

Just remember, NEVER use household cleaning products to remove pool stains! Doing so can bring phosphates and other problematic chemicals into your pool water. Always use products specifically formulated for pool use.

Organic Pool Stains

Organic contaminants in a pool can discolor surfaces just as quickly and easily as metals and minerals can. Something organic, like tannins leaching from leaves, acorns, or mud sitting in the bottom of the pool, often causes a greenish-brown colored pool stain. Algae, worms, or other animals can also leave behind ugly stains on pool surfaces. Berries from surrounding trees and bushes can also discolor a pool, and will create a red or blue stain.

The best defense in this case is to maintain a clean pool and keep contaminants to a minimum. If necessary, do a bit of lawn work to reduce the amount of tree and shrub debris entering the pool. Use a leaf rake or skimmer to remove large debris on a daily basis. Then, run the filtration system to remove fine debris in the water, and use a vacuum or automatic pool cleaner for sunken particles at the bottom of the pool. As we mentioned earlier, enzymes can help break down organic contaminants and oily residues. This will also help your sanitizer work more efficiently and reduce your chances of organic pool stains appearing. Enzymes are a MUST when closing the pool for the winter.

Treatment and Removal of Organic Stains

A simple way to get rid of most organic pool stains is to shock the pool and give your pool a little TLC with a good brushing. When that’s not enough, organic pool stains in concrete pools can usually be “bleached” away with chlorine granules sprinkled over the area. Vinyl pool owners should pre-dissolve the chlorine first, then pour directly over the stain. If not, try the methods mentioned above for removing metal and mineral stains.

Stain Eraser

To skip the harsh chemicals, consider using a Stain Eraser. Available in types for vinyl or concrete pools, this product serves as a mild abrasive, enhancing your stain scrubbing efforts. It also comes in handy as a tile grout scrubber to get in between those fine cracks. The tan eraser is for concrete pools, and the blue eraser is for vinyl pools. Both easily attach to your telescoping pool pole for hard to reach pool stains.

Some of the worst pool staining can occur from mudslides, mulch, or soil overflowing into the pool. When correction is impossible, dark-colored plaster or a pool liner can conceal certain stains.


We hope these suggestions enhance your understanding of pool stains and offer effective removal and prevention methods. Again, the easiest way to deal with pool stains is to prevent them from happening in the first place. You can do this by keeping your pool clean, your chemical levels balanced, and your metals and minerals properly sequestered. An ounce of prevention is worth a pound of cure, or in this case, a hassle-free, beautiful pool.

In the event that you do find yourself struggling with difficult pool stains, we’ve assembled a series of useful tips for you based on the different pool types:

162 thoughts on “Swimming Pool Stains Removal Guide

  1. I have a brand new gunnite pool. The French gray plaster was sprayed and filled up on 9/14/20. The water was clear and pretty. The pool builder came ion 9/15/20 and put in start up chemicals and 6 chlorine tablets in the skimmers. Hours later the pool was so green that you could not see the bottom and at night you could not see a foot in front of the light. We called the builder and told them
    something was wrong. They said it will be fine, give it time. Then said “o do you have well water?” which we do and told them from the beginning. Never coming to see the pool, they still proceeded to say give it a couple days it will clear. It got worse. On 9/26 the pool builder tells us we build pools, we don’t do chemicals, you can take a sample to have your water tested. We took a sample and told them it was a new pool and were told to put metal out, stabilizer, shock, and Muriatic acid. The next day no better at all. Took a sample to another pool place. They sold me bio guard pool
    Magnet plus – said I would see results by next morning. We did not. Went back and they sold
    us another one said we should have put 2. You can see the bottle of the pool now when standing over it. The plaster is stained. On Thursday 9/24 the pool company sent someone but still has not
    come themselves. The guy said the plaster is stained and he would report back to them. He added some metal control bags to the skimmers and said he would be back on Monday. The pool company called Friday night 9/25 and said they were trying to figure out what to do – may have to drain pool and acid wash. This is brand new plaster – the water Is clear but has a very green tint – nothing like blue color that it is supposed to be. Do you have any recommendations for cleaning the whole pool (it’s not just spots) without draining and acid washing and starting over?

  2. Leslie Crocker

    We made a mistake and cleaned our glass tile with a steel wool brush . Small particles went into the pool and there are numerous small rust spots across the bottom of our white Fiberglass pool and steps. Any suggestions on where to begin? I read we could try dry acid in a sock and tie to a pole .

    • Yes, try the “Stain Sock” idea, just pour 1 lb of dry acid (pH decreaser, aka sodium bisulfate) into an old orphan sock, preferably a thin sock, tied tightly and tied onto a pole, and moved around every minute or so. If that doesn’t work too well, we also have a product called Stain Eraser, which is kind of like a giant pencil eraser that fits on a pool pole and used for scrubbing stains. Use the one for vinyl liners, it’s a bit softer.

  3. I have a 5 year old 10,000 L above ground vinyl pool. A green stain has spread over a large area of the floor and when I sweep it with a brush, it lightens, but still stays. After a day it will be back to its regular greenness.

    Also, the green tends to spread a bit along the floor the next day, but if I brush that, it tends to come off.

    If I put a chlorine puck directly on a stained area for a few minutes, the stain completely goes away.

    Does that mean it is organic and I should just shock the pool? Is there a specific chemical and form of it I should use? I live overseas, so brand names won’t help me – I need the generic names…

    Thanks in advance.

    • Hi Rob, yes I would shock the stain, with a granular chlorine, like Calcium Hypochlorite (Cal Hypo), or you can use Di-Chlor stabilized shock. With a low pH of 7.2-ish, broadcast across the surface, and let it sit for up to 60 seconds, then brush with your pool brush. Caution, this method could possibly bleach your liner, but since you put a tablet on the floor, I figure you ain’t skeered. 🙂 Then, try to keep chlorine high for the next week, with a low pH, and if you really want to fight back, replace your filter media, (sand or cartridge), or use a good chemical Filter Cleaner (or TSP soak to remove oils, followed by a mild acid bath for cartriges).

  4. Gwendolyn Monroe

    This is a 40 + year old inground pool. There are two kinds of stains, a very dark, almost black four round spots in the shallow end, all together. The largest is about 8 ” in diameter. And there is a dungey yellow-brown stain that is all over the place. I want to get rid of both. How, and is there a way to tackle them simultaneously? I wish I could send you a pic

    • Hi Gwen, the large dark stains, could they be the gunite showing through, or bare spots in the plaster? You will want to drain the pool and pressure wash then acid wash the pool. Once drained, you can inspect the large stains closely. If they do appear to be bare spots in the plaster, use our EZ Patch #1 plaster mix to patch the areas, after acid washing, and fill the pool immediately, keeping the patched areas covered in wet burlap or other heavy breathable fabric, or keep them shaded and moistened, until the water level rises over the patches.

  5. Dan Korzec

    I have an in ground pool and I just found a grayish black stains on my fiberglass stairs. There is no staining on the vinyl liner. Chemicals are balanced and the copper was just a bit high when last tested. This appeared almost overnight and nothing drastic has happened except the excessive heat in the northeast. Any ideas?

    • Copper can drop out of solution like that and make ‘gray ghosting’ stains or mottled black areas. It can happen from shocking the pool or other sudden water chemistry changes. Try Jack’s Magic The Step Stuff, since you don’t see it on the liner.

  6. I have an above ground pool and have some white stains on my liner at the bottom of the pool. Looks like a bleach stain Any ideas?

    • Hi Paul, could be – esp. if someone has put pool shock directly in the pool, or pH decreaser, without pre-dissolving. And it is permanent, I’m afraid. But don’t stress too much, the water still feels good, and after awhile you won’t notice it anymore. 🙂

  7. We have a fiberglass swim pool that had scale and some metal stains. We added a scale and stain remover a week ago. It removed the stains and scale but now we have a very cloudy pool. It gets worse when we brush the pool. What can we do to clear this up?

    • Hi Tracey, add a Clarifier, per label dose, and run the filter 24/7. Also could benefit from a Filter Cleaner chemical. Also check the alkalinity and pH levels. Low alkalinity and pH can cause what we call ‘chalking’ on fiberglass and painted pools.

  8. Anne Kelley

    Hi, I have blackish grey staining in my inground pool. It has gotten worse over the last year. One pool person came out and without testing said it must be black mold and I would have to have my pool re-platered by his company. After looking up what balck mold looks like online, the stains do not appear the same. They are flat and mottled looking. My pool is not new. We have tried shocking with no results. Could the dark grey stains be from copper?

    • Yes, they could be from copper, mixed with other stuff. Could have some iron there too. You can test acid wash it if you have some near the top of the wall, just lower the water level and pour a 50/50 acid/water mix, from a flower watering can, and see how easily it removes, which my guess will be instantly, then you can decide if you want to do a full acid wash.

  9. Hi . How can I remove rust stains from nails on walls of terrazo pool? Big pool so would rather not have to drain it!
    Thanks Susanne

    • Hi Susanne, on the walls you say? Is that from nails that are in the wall? If so, you’d want to remove them, or removing the stain will be only temporary. To remove, you can make a “Stain Sock” or use a Jandy Stain Master, or just a PVC pipe with elbow fitting. A Stain Sock is an old, thin sock, filled with about 1 lb. of dry acid, aka pH Decreaser, or our EZ Stain Remover chemical. Jandy Stain Master is a device that works with a gallon jug of muriatic acid (sold separately), and delivers acid to the 3″ cup attached to your pool pole, allowing you to do mini acid washing of small areas, such as rust stains or spots. Third, use a PVC pipe and a 90 deg fitting at the end. Submerge the pipe so that the 90 is positioned over the stain, hold it firmly and have a helper pour in a few cups of muriatic acid or dry acid. Keep holding the pipe against the wall for a minute or two, moving it slowly as needed, to do an ‘underwater acid wash’ of small areas or spots.

  10. Christie

    Hi, last year we got the inthe swim kit with sulfamic acid and I think TSP. It worked great but this year since our plaster pool is getting old and has some pocking and pitting and a few stains from metal toys the grandkids threw in we decided to paint it. We cleaned it with tsp but it still has some pale blueish algae stains I assume since we kind of let it go over the winter. Can we paint over them without worrying they will come through the paint. What type of paint is best for a plaster pool in Arizona.
    Thanks,

    • Hi Christie, Epoxy paint (Super Poxy Shield) is the best paint, for any climate, with the longest lifespan. Did you also acid wash the pool? This will remove most stains. The usual paint prep is “TSP – Acid Wash – TSP”. The TSP removes any grease/oil, and the Acid removes calcium scale and roughens the surface.

  11. I have what I believe to be a vinyl in ground pool that I have drained to work on tile and some rust stains on the bottom. I was told to use muriatic acid to remove the stains. I am finding how to clean stains from a pool that is full but not one that is dry. Can anyone tell me the best way to go about removing these stains?

    • Hi Jim, if the pool has tile around the waterline, it is probably not a vinyl pool, but could be fiberglass. If the bottom is cementitious, it could be plaster finish, in which case the diluted muriatic acid is the best stain remover. Rinse thoroughly after use. You can use an acid solution on fiberglass and vinyl too, but very carefully!

  12. Antonino

    We made a mistake of adding shock and now we have white stains in the bottom of our pool. How can we romove this stains.

    Thanks in adavnace

    • Hi there, if you have a vinyl pool, these would not be stains, but areas that are ‘bleached-out’, as we say. There is no way to restore the color that I know of, lamentablemente. Sorry for the bad news. 🙁 In the future, pre-dissolve shock into a bucket of water before pouring into the pool, or use non-chlorine shock.

  13. I made the mistake of adding acid when the pump was off. It caused something in the pool finish to turn blach in spots where the acid touched. It looks like frecklees. Is there a way to fix this?

    • Hi Thomas, that is likely a metallic stain, like copper or iron. Dramatic changes in water chemistry can ‘knock’ metals and minerals out of solution. I would add a sequestering agent, like our Stain Away or other “Stain & Scale” product, in the hopes that it will redissolve the metal back into solution. Some brushing of the area may help.

  14. Donna Webb

    Dumb question from first-time above ground pool owner: To use all the stain removers you mention, am I supposed to drain the water out of the pool first?

    • Hi Donna, no just sprinkle the granular over the area. The only exception is where I discuss an “Acid Wash”, which is done with an empty pool. An exception to that however, is the “No Drain Acid Wash”, a method of lowering the pH level to near zero – but still not as effective as draining and acid washing the plaster/concrete (not done with vinyl pools).

  15. Stefanie

    I have a 20 x 40 inground salt water pool in Georgia. What pool cover would you recommend when we close the pool? We have a center step at the shallow end. Also – the 2 ladders, inside the pool, won’t seem to come out. Are there covers that fit around ladder rails?

    • Hi Stefanie, it would be unusual for the ladder rails to be non-removable, but it is possible. IN such cases, safety cover manufacturers can sew-in “cut-outs” that fit around the ladder rails, when provided with detail measurements and photos. This will however, increase the cost of the cover by a lot, and complicate install/removal, so you may look again, and if truly not removable, consider cutting them out, and installing new ladders, with standard deck anchors, to allow removal at closing. A 20×40 rectangle with center end step is a standard stock cover size, and get one of these 20×40 safety covers The solid safety cover will be the best choice for stain prevention, even better is solid without a center drain panel (not shown but can be ordered), which will keep nearly all stain producing water, dirt and oils out of the pool.

  16. Kim Babbie

    Orange particles on white stairs and orange/brown stains which disburse in water when vacuming. Backwashing shows orange/brown particles. Not sure what to do and pool stores not helpful. We have a 24′ round above ground pool which has always been fine. For issues beyond our control we were not able to keep up with pool chemicals and developed initially some green/yellow sporadic stains on the bottom which looked almost like pollen when vacuuming the pool. Added shock and algeacide but spots kept growing. Water started turning hazy and added more shock and chlorine. Also we were using tablets in two chlorinators in the pool. Temps were high with lots of rain for several weeks prior to stains appearing. Tested the water upon return and found PH (6.2) and Alkalinity (30-40) very low. Hardness also low at 150. Free chlorine is 3 which test says is normal. Added sodium bicarbonate to bring up alkalinity and water immediately turned green with orange/brown particles and patches bottom. Brought up Alkalinity to 60 but PH still at 6.6. Working on bring PH and Alkalinity up using sodium carbonate. What could be the orange/brown particles and why turned green so fast? Water test at 3 pool stores showed 0 for copper. What can we do to get rid of the orange brown? Any help is appreciated as pool stores keep saying to just shock the pool.

    • Hi Kim, an unusual reaction, upon adding alkalinity increaser. The orange particles could be Iron, or it could be wind blown clay dust, from a nearby construction site. Have you tried using a Clarifier to assist the filter in removing the particles? Your filter may be overwhelmed, filtering longer each day can help.

  17. After adding calcium chloride to balance water hardness my pool (25k gallons, vinyl liner) has developed large blue-green splotches over 20% of the pool surface. The splotches developed within 24 hours after balancing the water so I doubt it’s algae but just to be safe I added an algaecide and scrubbed with no visible improvement.

    I don’t believe the calcium chloride discolored or melted the liner, the area where I added the chemicals is not discolored and the splotches appeared at random locations.

    I have read this may be a result of copper or other metals staining the liner, is there a way to to test and what should I try as far as cleaning or stain removal products?

    • Hi David, most likely copper. large movements in water chemistry can cause metals to ‘drop-out’ of solution and stain in random ways. Recheck all water balance and make sure pH, alkalinity and calcium are correct, then add an initial dose of a good sequestering agent like our Stain Away, or Metal Free, or Jack’s Magic Blue Stuff, and with some luck it may reabsorb the metal into solution. If not – treat the stains by sprinkling Stain Free or A+ Stain Remover, both ascorbic acids that are good with metal stains. Then, continue to use sequestering agent, with maintenance doses, because it depletes in 2-3 weeks time. Culator is also a good product to consider, the only one that will actually REMOVE metals from the water – sequestering agents just keep them dissolved in-solution, and make it harder for chemical changes to knock them out…

  18. Hi. We’ve had dark stains on our inground vinyl pool liner for over a year in some of the corners. New stains are developing by the day in the center of the pool. I rubbed some vitamin c tablets over one of the darkest stains and it lightened in color. Which products should I be purchasing? I had the water tested today at a local pool store and all values were in normal range. I have many photos but don’t see how to add them here. Thank you so much!

    • Hi Shanna, if the Vit C test works, that usually means that the stain is mineral/metal in nature. Treat the pool with 100% ascorbic acid, like found in Stain Free or our own A Plus Stain Remover. Follow instructions to balance water, add Stain Free, then follow-up a day later with Metal Free, or Stain Away to absorb the metals into solution, before the stain again.

  19. Jessica Alix

    Hi. We have an above ground pool about 5 yrs old. Every year when we open it, the vinyl top rail is stained brown. The water is beautiful though and while the stains lighten up thru the season, each year they are darker and cover more area. What could this be from? No other stains on the liner, above or below water line

    • Hi Jessica, I would guess it is from the winter cover, being pulled over the top rail, and perhaps rubbing a bit from wind and varying water weight on top of the cover. Winter covers don’t normally cause this to happen, or I would have heard of it by now, but that’s my guess!

  20. I bought a home last year in Jacksonville (North FL) and are new to pool ownership. We have a 13yr old SWG pool finished with “KrystalKrete” Quartz finish. This spring it got hot quick and our pool temp jumped from low 80s to low 90s in less than two weeks. During this time we slacked on the chems a bit and our PH became high,between 8.2 and 8.4 for over a week. We also had unusual drought conditions so I was constantly filling the pool with hard city water due to water evaporation. We also had high CYA during this period (over 80 below 95), due to using new granular that was more powerful than directions indicated. We noticed a Yellow brown light tint start to form on the finish last week throughout various spots in the whole pool, not just in one location. It is light but definitely a yellowish brown tint. It is mostly on the walls and
    slope of steps. We went through one whole season with no issue. The only thing that changed was our PH was high for a longer period than ever and we had to use more hard water than normal. What is your opinion and solution? Pictures look like it could be Iron or Copper possibly. Also, on a side note how do you keep your PH level balanced while keeping TA balanced, it seems quite difficult to keep our PH between 7.4 and 7.6 while keeping our TA above 80ppm. Our PH currently is 7.4, our TA is 70, Calcium is 350ppm, our FC is 15 (high due to scrubbing stain with chlorine tab), our CYA is 80
    Adam ODR $38.00 5/29/2019
    Paid to Adam Paypal

    • Hi Eric, when pH and calcium are both high, and water becomes warm, it’s a perfect storm for scaling. So if you have shocked the pool, but still see this yellow tint that won’t scrub off, it could be calcium scale, mixed with some algae and dirt. If it is fairly localized, you can use the Purity Pool stain remover tool, and some liquid acid to remove. Using a sequestering agent like Scale Free, or Stain Away will help bind calcium into solution so that it won’t come out of solution so easily during shocking, warm water or high pH conditions. To control pH and alk, some people like to lower alkalinity with pH decreaser, then raise pH with aeration of the water. For the recent cya rise you experienced, DiChlor shocks are stabilized, but Cal Hypo shocks are not, and have no cyanuric acid.

  21. Kathy Navaretta

    I have stains from the worms over the winter that I can’t seem to scrub out. I put the vinyl stain remover in-stains still there. They are yellowish in color-don’t think it’s algae. Any suggestions?

    • Hi Kathy, yes – lower the pH into the 7.2 range, and then sprinkle pool shock over the area. Let it sit for 20 seconds or so, then brush it off with the pool brush, using strong, hard strokes. Repeat if needed. They will fade naturally as well, within a few weeks of sun and chlorine. Keep brushing the area daily.

  22. We moved into our home in December and in January had the in ground pool acid washed and diamond brited. We removed trees on our property but many leaves still find their way into the pool and sink, leaving yellowish-brown stains that we seem unable to brush out. Is there a way to remove those stains (easily) without draining the pool? We’re new pool owners are slaves to the pool! Help please! Thank you!

    • Hi Jim, sprinkle a bit of regular chlorine pool shock over the area, for instant leaf tannin removal. Just bleaches them out!

  23. Hi we have recently bought a country home with an In ground concrete pool that was in an extremely poor condition more like a dam (including fish!) we have drained it and high pressure sprayed it but there is still a very Carl stain on at least the lowere half of the pool. Can we clean it or repaint it?

    • Hi Mardi, an acid wash procedure should be able to remove most staining, in most cases. This strips off a thin layer of plaster, so not something you can do every year, but in this case – yes. Such stains will also continue to lighten as the pool circulates and chlorine and sun work their magic, but without acid washing it will likely still be a visible demarcation of where the water level was… Painting will also work, but you will have to plan on re-painting the pool every 5-7 years (epoxy pool paint), or every 2-3 years with rubber or acrylic pool paints, as the paints will wear thin over time.

  24. our salt/chlorine machine had stopped working and it took us a couple of weeks to get the right one and to get it working correctly. Meanwhile our beautiful clear pool with hardly any stains on the bottom turned into a pond!!! Smelled like a pond and had little stringy things growing from the seams. also caused huge ugly stains on the bottom of the pool. We drained about half of the water, put in 5 gallons of bleach then used heavy duty brushes to try and loosen what was on the bottom. No luck, what was loose sunk right to the bottom again and has stuck like glue. ARGH and help!!!

    • Hi Lisa, tough luck – but a perfect example of why saltwater pools DO need to use chlorine tablets or shock from time to time, because when the pump/filter or salt system is not working… no chlorine is produced. First thing to do is to balance the chemistry, good pH/Alkalinity/Calcium hardness if that needs adjusting. Second thing is to run the filter nearly non-stop 24/7. Shock the pool again if it is still green-ish, and keep the chlorine high for several days. If the chlorine level drops to zero within 12 hours of shocking, shock again, but with a higher dose. Usually dead algae won’t ‘stick like glue’, so there may be other issues at play. A pool enzyme may be useful, like Pool Perfect or Pool Magic – which work well on sticky and oily substances.

  25. Paul struzziero

    my inground pool has copper staining (black) all over it
    do you have something we could add to fix, my pool guy is saying to drain and acid wash. i was looking for an easier solution

    • Davy Merino

      Hi Paul, you could try to reabsorb the copper into solution – which can work sometimes, almost magically. Balance the water and add a sequestering agent like Jack’s Magic Blue Stuff, or our Super Stain Away, or Metal Free (lots of options), just pour it in the pool and if you’re lucky, it will lift the copper from the surface and redissolve it into solution. If that doesn’t work, then yeah – an acid wash would be the next best solution. Also look to the source of the copper – copper algaecide? copper heater heat exchanger? copper in the water supply? copper pipes? copper pool ionizer? So that the problem won’t reoccur.

  26. Jason Tran

    My pump motor went out on me for about a month and just now I’ve finally get to drain out the pool completely. The surface of the pool seems to be in good condition; however, there are light brown stains and light green algae spots everywhere. I tried to remove them out with water and a brush but they don’t seem to come off. What specific product should I use to remove these stains while the pool is dry?

  27. Paulette Austrich

    We just moved into a home with a pool that had been maintained by the former owners. The house was left unattended for a few weeks with the programmable filter running 4 hrs a day instead of 8. There are no tall trees nearby (only evergreens) so we’re not sure why we suddenly have dark green/blue stains all over the bottom of the pool. It wasn’t like that when we first saw the house. We had to be away for a month before moving in and hired a service to maintain it but they took a while to begin and algae built up (according to our neighbor). We just got back in town and there are a lot of dark stains all over the bottom of the pool. What do we do?

    • Hi Paulette, probably started from running the pump only 4 hours per day – during summer, most pools need at least 12 hours per day of filtering and sanitizing. Dark stains green/blue sounds like algae – lower the pH to around 7.2 and shock the pool with a heavy dose of chlorine pool shock, then brush the pool and run the filter 24/7 until it clears. Then begin to use an algaecide, adding weekly maintenance doses to control the algae, and help chlorine to kill it as it forms.

  28. Help! – while treating for stains we now have algae and we are only on day four of the stain free treatment. It says not to shock for a week but algae is getting out of control. How do we proceed?? Do I need to bring up chlorine slowly prior shocking?I don’t think we can wait for that.

    • Hi Kar, yes I would go ahead and shock the pool, first lowering the pH level back down to 7.2-ish, so the chlorine is most effective. After 4 days, now 5 – the treatment should be done, or done all it is going to do… then brush and filter, etc

  29. My pool was replastered this past December. I live in Arizona and a couple of days ago we had our first Monsoon storm. The pool now has many stains. They look like sand and will not come out.First of all,why did this happen,and what needs to be done ?

    • Hi Frank, I have a theory… if your pH was very high, which happens with new plaster, and your calcium hardness was very high, which happens in AZ, a precipitation of the calcium may have occurred when the pool was shocked after the monsoon, or perhaps without shocking, which mixed the airborne sand and calcium together into nodules or crystals, which deposited on the surface. Try scrubbing them with a pumice stone, and lower the pH level first to 7.2-ish. With a lower pH, and the use of a sequestering agent, they may dissolve (from the lower pH), and the calcium reabsorbed into solution, and held in place with the sequestering agent (Stain & Scale). IF stains persist, treat with EZ Stain remover.

  30. Ok- dealing with these stains this year and need help! (Wanted to insert pic here but can’t see how. Perhaps email to you??) Dark brownish spreading stains, not removed by brushing or vacuuming.

    Vinyl inground salt pool 15×40 w 9 ft deep end, new pump, DE filter, clay soil
    Have tried extra shock, metal out, culator pod, algae treatment, and brushing often
    Seems a little better sometimes ( but never gone)

    I read on one of your blog posts of the possibility of growth UNDER the liner showing through. We hadn’t considered that. How can that be dealt with?

    • Hi Kristin, growth under the liner is primarily associated with sand floors, and sometimes vermiculite, and of course would not be on the walls, just the floor. It is dealt with by a new liner, and new floor material, quite an expensive process. And it may return? Not sure how one could fully prevent, although using a liner floor pad could help – normally used on aboveground pools and not really recommended for inground pools. BTW, Metal-Out (sequestering agents) are not a one time treatment – if it is metal staining, those products need to be added regularly (and forever) to be effective. Dark Brownish stains might be associated with iron or calcium, but may also be clay getting into the pool during heavy rainstorms? But normally would be removable… dirt.

  31. My pool is full right now, when we opened it up there was A lot of debris on the bottom once we had the vacuum clean all that up Some of the debris is stuck to the bottom and will not come off Is there anyway to get that off the bottom without emptying the pool. Thanks

    • Hi Dawn, first balance the chemistry, with proper pH, alkalinity and calcium levels, then shock the pool with chlorine, allowing the granules to bleach out the stains briefly, then brush well with a good pool brush. Repeat if necessary, and stains will fade with high chlorine, low pH and lots of sunshine. If still not gone after a few weeks, try our EZ Stain Remover or A+ Stain Remover.

  32. Hi Leslie, I have brownish red stains which appear on my liner. First let me tell you I have a 12500 gallon in ground vinyl liner pool with a salt generator . The liner was recently replaced and ever since then I have noticed brownish red stains which are easily vaccumed up. What do you think might be causing them?

    • Hi Todd, if they easily vacuum up, I would guess some sort of pollen/dust mixture, or clay soils washing into the pool, or blowing in on the wind. Could be a filter problem, especially snd filters have a problem with very fine silt.

  33. A racket was left on the bottom of our pebble tek Pool and has left a rust stain, what’s the best solution to get it out?

    • Hi Karina, depends on how deep and dark the stain is. If a light surface discoloration, use EZ Stain remover, sprinkled over the area, A Plus Stain remover works too. Scrubbing with a Pumice stone may also be needed, to remove fully. For heavier stains, a Jandy Stain master device may be needed, to deliver muriatic acid directly to the source, a localized underwater acid washing.

    • Cindy marie

      How do I remove black rubber stains from water shoes?

  34. John Bublitz

    I have a 10,000 gallon fiberglass pool that is filled with very hard well water. After opening the pool was very clear but over night it looks like metal precipitated from suspension in the water. Now I have a brown stain covering about 2/3rds of the pool. It will not brush off. What is the “best” product to add to the water to remove the stain? I cannot drain the pool. Thanks for any advice you can provide.

    • Hi John, with very hard water, you likely have a mix of scale and metals, precipitated out of solution, and deposited on the surface. The first step would be to start with balanced pool water, using an LSI calculator, and then add a Stain & Scale treatment like our Super Stain Away, Metal Free, or Jacks Magic Blue Stuff. Sometimes, that will be all you need, and the metal will redissolve into solution with a little brushing of the pool. If not, you can broadcast a stain remover chemical (mild acids) over the surface, try A+ Stain Remover or StainFree, both Vitamin C based ascorbic acid – or if that doesn’t work well, try EZ Stain remover. Good luck!

  35. Mike Neders

    Hi, kids left the house and no one using the pool so we drained it and let it sit for a few years. Leafs a dirt caused some serious discoloration. Now we want to open and the power washing is not getting it clean. Thinking acid wash but is their something easier? No water in pool right now. Thanks

    • Mike, acid washing is the way to go – and it’s not difficult actually, but does require some knowledge to avoid damaging the plaster, and some breath control, to avoid the harsh gas. Read up online in several spots before beginning. I recommend a flower watering can, (with spout) as the best way to evenly pour the acid/water mix onto the surfaces. Start with 50/50 mix, and then you can go stronger if needed. Be sure to neutralize the waste water with pH decreaser before pumping out.

  36. I have a vinyl lined inground pool. Last year the bottom of the liner started looking like it had creamy white/yellow cloud looking stains all over the bottom. I have metal free and stain free chemicals, but I am unsure how to apply these to get rid of the stains. Do I have to lower the chlorine level to .5 first and how do I apply the chemicals.

    • Hi DeAnn, the Metal Free is used to hold metals and minerals in solution, to keep them from coming out of solution (precipitating), where they can attach themselves to pool surfaces (causing stains). It is a product known as a sequestering agent, because it sequesters (holds) minerals and metals in a dissolved state. The Stain Free is a mild acid stain remover made by ascorbic acid (vit C). It is sprinkled over stained areas as a stain remover. Both bottles have very precise water chemistry guidelines along with application and dosage information, which will tell you better than I can…

  37. While painting the pool deck today,the roller dripped some paint into the pool and it settled on the vinyl liner. Any ideas on how to remove the paint would be greatly appreciated! Thanks for your time

    • Hi Diane, maybe it would scrape off? Gently of course. Otherwise, might scrub it with a textured sponge. Any solvent would likely damage the liner print and maybe the liner, but if you are desperate to remove it, some diluted paint thinner, just drops on a sponge, could be tried in a small area, as a test.

  38. I have a 22,000 gallon pool that I install pebble Tec on three years ago. Developed a white white streaky discoloration down the middle of the pool that almost looks like the Milky Way on top of my blue surface. Wondering how I can best get rid of this as I consistently brush the pool but it does not seem to make a difference. Please help I’m going very frustrated as this beautiful pool looks as though white has been sprayed down the middle of it

    • Hi Gregory, that sounds like a calcium discoloration, a scale. If you can drain the pool below that area, an acid wash would be the best treatment, but if not possible, I would try using a Jandy Stain Master to deliver acid to the area. You can also try our EZ Stain Remover, with a low pH, followed by treatment with Scale Free or other sequestering agent (there are many). Sprinkle the EZ Stain over the area, let it sit following directions, then brush off. Then treat with sequestering agent to lock calcium in solution.

  39. Need to remove a large stain form the pool being drained after acid bath but left remaining dirty water sit in bottom for two days. left an 8′ ring and company won’t do anything about it. Any suggestions? Thank you

    • Hi Carl, you could give EZ Stain Remover a try, an acid based granular stain remover, sprinkled over the area, with the drain off, or pump turned off for an hour or so, then brush and turn on pump again.

  40. Hello, we just opened our inground pool & there’s a rust stain from a screw that had fallen in before it was covered for the winter. How do we remove the rust stain? Pool is full of water. Thank you

    • Hi Marie, for a vinyl pool, rub it with a stain eraser for vinyl pools, but for plaster pools you can use a pumice stone. Both should work well, but if not perfectly, on a plaster pool you can use muriatic acid, poured into a long piece of 3/4″ conduit or pvc pipe, held right over the stain. Jandy Stain Master is another product that can deliver acid to a specific spot in the pool, for ‘acid washing’ small areas.

  41. richard routhenstein

    have a grey marble dust gunite pool old style pool cover this year when i opened it had lots of brown stains in the deep end used vitamin c and it took alot of it away but some still remains any solutions chemicals are perfect no metals present

    • Hi Richard, when the Ascorbic Acid (Vit C) works, often chlorine shock will also work (for gunite pools inground). Sprinkled over the area on a sunny day and it will help bleach it out. Let it sit for several minutes with the pump turned off, probably would use 2-3 lbs of our ‘super pool shock‘. After 5-10 mins, turn on the pump again and brush the area with a pool brush.

  42. I had algae and put algae use in my pool – shocked my pool have had to vacuum every day- my pool is finally not green – the water is still not clear and cloudy and like a light brown dust on bottom of pool – I can’t get my water clear – I have a sand filter and backwash everyday

    • Hi Sheri – backwashing every day – sand filters work better when they are a little dirty, and sand filters have trouble with very fine debris, using a Clarifier can help, or a product called the Slime Bag can also be used, to trap the small silty debris. Also, you may need to run the filter 24 hrs for a few day, if you want faster clean-up. Keep the chlorine level high and the pH level low, keep filtering, add clarifier, and backwash only when the pressure is 8-10 psi higher, or if flow is noticeably diminished. Now… if you HAVE to backwash daily, because the pressure is rising within one day… you probably need to replace the filter sand – large sand filters may go 8,9, 10 years even between sand changes, but small sand filters (under 24″ – or too small for the pool size), may need new sand every few years.

  43. Hi Dave! Went to a mesh cover this year not sure if it’s part of the problem but we have clear water and great chemical readings according to our pool place. But we have some greening on the floors and walls that will not scrub off. Held a chlorine sock in place with no impact. Did same with vitamin c tablets today and a good amount of one stain disappeared. These were small vitamins from cvs.
    Now how do we apply vitamin c over a very large floor area including walls? The pool is extremely large. What’s the best application approach given the size and verticals and next steps now that we’ve identified the metal stains and that the citric works?
    Thanks for your help!

    • Hi Joe, yes sounds like copper staining, which can come from source water, copper pipes or copper heat exchangers in pool heaters – the first thing I would do is start using a good sequestering agent (AKA Stain & Scale chemical), to keep metals locked in solution during dramatic chemistry shifts like a large pH adjustment or heavy shocking of the pool. Any one of the many can be used – Stain Away, Jack’s Magic Blue, Metal Free… but the chemical degrades in sunlight, so you have to be regular adding ‘maintenance doses’ every 1-2 weeks. In some cases, just adding the sequestering agent will lighten or completely remove existing stains – so start there. Then if you still have staining after a week or two – get StainFree or our own A+ Stain Remover, and for the floor just broadcast, but for the walls? Yes, you raise a good question. Stain socks don’t work very well with Vit. C (ascorbic acid), as they dissolve quickly, so the best bet is to just pour a bit down the wall, and brush, however it may not do much, so test a small area before you dump in too much down the wall (the stuff’s not cheap!). If needed, the walls can be acid washed, without acid washing the entire pool, just lower the water level to within a few inches of the shallow end floor (concrete pools only), and pour a 3:1 water:muriatic acid mixture, from a flower watering can along the pool tile, enough to coat the wall evenly in a 5 or 10 ft section, then rinse off within 30-45 seconds. Repeat or adjust strength as needed. Afterwards refill the pool, and add pH increaser to counteract the acid (pH decreaser) that was added.

  44. Had our gunite pool marble dusted 2 years. the walls and steps feel like sand paper. How can I correct this?

    • Davy Merino

      First determine if these are deposits, crystals on the surface, or if the surface is pitted and etched. For newly plastered pools, the pH rises during the first year, and during winter, a very high pH combined with high calcium levels, can produce crystalline deposits on the surface. These can be acid washed off, after draining the pool, or they could also be sanded lightly with belt sanders (don’t use orbital sanders), with a light grit that is sturdy enough to do the job, or even hand sanded with sanding blocks, for small pools.

  45. Rob Carlyle

    I am having issues with my pool. I cannot keep my chlorine up and Iam getting yellow stains on my pool steps and and where the water comes out in the pool. It cannot be scrubbed away but Stain Free works. It keeps coming back. I have shocked my pool and super chlorinated the pool. I have a salt water pool and I have had it for a year and a half.

    • Davy Merino

      Hi Rob, if you cannot keep the chlorine up, that indicates either the salt level is low, or the salt cell output is low, or not being run long enough each day perhaps. However, it could also be poor water balance, like high pH and low alkalinity, low hardness and stabilizer levels. It can also be that there is something consuming the chlorine or making it lazy… high levels of combined chlorine (over 0.3 ppm), or high levels (over 300 ppb) of Phosphates or heavy organic debris, or heavy pool use (lots of swimmers). it can sometimes indicate poor filtration; if the filter is not doing it’s share of the work, the chlorine level can become overwhelmed. Shock the pool heavily for combined chlorine, and use phosphate remover for phosphate/nitrate removal. Now for the stains, a lot of people get these on the drop-in type steps on vinyl IG pools. Stain Free does work well yes, we also have a cheaper private label version in our A+ Stain Remover product. I would recommend that you try a good sequestering agent like Metal Free, or our own Super Stain Away, follow instructions for initial dose and use follow up doses for 2 months, and see if that won’t prevent the stains from returning.

  46. […] Most pools tend to need either pH Up or pH Down more often, but pool owners should have both on hand. Pool pH Decreaser is also used to lower Total Alkalinity, and also for pool stain removal. […]

  47. I’m going ti be putting up a pool that was stored over winter and I want to clean and scrub it before filling it up. Is there like an all-purpose cleaner you can suggest for that? There aren’t really any stains that I can see, just some dried up dirt from the bottom that has gotten on the inside from storing it

    • Davy Merino

      Hi, you can use Simple Green or Spray Nine, or use our Tile & Vinyl cleaner product. And a good scrub brush, or even a soft push broom. and lots of water, and sunshine!

  48. I put too much shock in my pool. It has left the white rubber pool steps leading into the pool a light brown and plastic pool ladder steps the same. Anyway to correct this? Solutions, paint, etc? Then I put some vitamin C tablets on the steps and they are now white again! Will the stain come back or should that take care of it? Thank you, Cassie

    • Davy Merino

      Hi Cassie, probably what happened is that when the pool was shocked (at this particular water temperature, and specific water balance: pH, calcium, alkalinity, etc) – it knocked out metals (probably Iron), and this deposited on the steps. Your quick action with the Ascorbic Acid saved the day! 🙂 Two products we sell are Stain Free and A+ Stain Remover, both a granular Ascorbic acid, but ground-up Vitamin C tablets (with or without Rose Hips, lol), also works as well. Now to your question, you still have the iron in the pool, floating around, and it could happen again the next time you shock, or have some other water balance adjustment with a lot of reactions going on. To prevent this, start using a sequestering agent to keep metals dissolved in solution. Stain & Scale chemicals such as Metal Free, Stain Away or Jacks Blue Stuff for Vinyl Liners, also very good. Add the initial treatment, then reapply following label, because it degrades in 1-2 weeks time. But if you use regularly, metals will stay locked in solution, even with dramatic water chemistry changes. Have a good summer!

  49. Hi there. I recently put chlorine tablets in an old floating container. Well it sank to the bottom of my play pad and made a perfect black shape of the container. I have a 3 year old quartz pool and don’t know what caused this or how to get it out. Any help would be appreciated.

    • Davy Merino

      Hi Nick, chlorine stains such as this can be difficult to remove. You can lighten it however with muriatic acid. Get a gallon, and a bit of 1.5″ or 2″ PVC pipe. Hold the pipe over the area and carefully pour in the acid, about 1 quart. Hold the pipe firmly on the surface, and move slightly around the area. Release after 1-2 minutes. Brush thoroughly. Repeat as needed. Wont’ remove it fully, but will lighten the stain. If you lower the water level, you can pour the acid directly on the surface, a bit more effective.

  50. P. Bonfil

    My empty spa is full pf dark stains on the vinyl liner, is there any product you can advise me to use to at least fade them.

    • Davy Merino

      Hi there – vinyl needs to be treated carefully as you know. Since it is drained, I would first try regular dish soap and a textured kitchen sponge. You can test try using Comet or Bon Ami, or other chlorinated cleanser, but use sparingly and rinse quickly, and pump out waste water quickly, as it is a bit harsh to vinyl.

  51. My pool company let me borrow their leaf scooper/basket at closing and I pushed it along the bottom to get the last few leaves up before the tarp went on. The basket was black and my pool is white and it left gray scrape marks all over wherever I used it that do not scrub off with our pool brush. Any suggestions? I’m thinking perhaps to try a pumice stone…

    Frustrated that a device designed to slide along the plaster surface would mark it up, and that my pool company would ever use it.

    • Davy Merino

      Hi Kevin, it is likely a plastic residue, so maybe before pumice stone, scrape it hard with a putty knife, and then use a stainless steel wire brush. Pumice stone could also be used, but first try to scrape off any heavy residue, so it won’t smear it around.

      • Mariano Alasaas jr.

        Sir when im going to fill the pool with water coming from a overhead tank there is a rust coming with it,then its hard to make a bluewish and its already in a greenish status,what should I do sir,?

        • Hi Mariano, balance pH/alkalinity,start to chlorinate slowly and filter the water, but do not shock with heavy chlorine right away, until you are able to circulate a sequestering agent (aka Stain & Scale chemical), to lock up the Iron and other metals in solution. Otherwise, shocking may knock metals out of solution, where they can cause staining. If available to you, pre-filters like the Pleatco one, can be added to your fill line or hose, to remove the metals as the water is added to the pool.

  52. Hi 👋 i have had my pool for several years above ground ..had very hot,lots of rain summer …the bottom of pool in a large area is stained green looks like algae stain we have tried scrubbing with brush as pool is filled with water we only use intheswim super shock every summer and it always works beautifully however im stumped as to how to remove these unsightly stains please help

    • Davy Merino

      Hi Corrine – Some stains on vinyl pools, those that don’t brush up, could be from algae or other vegetative matter growing UNDER the liner, and showing through. Heavy mold and mildew can do the same thing. But before you assume that – I would first try the In The Swim shock, raising chlorine level very high, to above 30 ppm, with 2-3 lbs of shock per 10,000 gallons, and a suitably low pH level of around 7.2 (be sure to pre-dissolve shock in a clean bucket of water) If that fails to remove your stain, try our EZ Stain Remover sprinkled over the area. If that doesn’t work, you could then try A+ Stain Remover, the vitamin C treatment. You can first try a sample of crushed up Vit C tablets, in a small area, to see if ascorbic acid (the active ingredient in A+ Stain) will work.

  53. Tracey Nixon

    Our house has a beautiful pool, but within the past few weeks or so we have noticed that the sides of the pool were green. We figured it was from all the rain we had been having but we can’t seem to get them to go away. We’ve treated the pool with shock, cleaned out the filter really well and added the DE as needed and scrubbed the walls really well. Is there something else we should do? I have mentioned muriatic acid but he frowns upon it every time I say something. Could you please help me?

    • Davy Merino

      Hi Tracey, does it scrub off with a brush, is it algae? Or is it a green stain (copper?). If algae, you can remove it with a high enough chlorine level, that may take a triple dose sometimes, perhaps just a double dose in your case. If not algae, (won’t come off with brush or chlorine), it must be a metallic stain. Could be copper, makes a greenish blue teal color. You can use a sequestering agent, like Stain Away or Metal Free, or Jacks Blue Stuff, to lock up any remaining metals in solution, and it may do a little bit to remove but will mostly just prevent it from getting worse, but sometimes it can actually remove metal and mineral stains, too. Let me know how it comes out. If it is just on the walls, these stains, it’s fairly easy to do a “wall acid wash”, just drain only 1/3 to 1/2 of the pool, and pour a 50/50 blend of muriatic acid / water solution down the walls with a flower watering can, with the threaded end cap removed. Let it sit only for 30-90 seconds, depending on strength and rinse off quickly and thoroughly with a hose. Once the water is lowered, you could do it all with one or two gallons of acid, in about 15 minutes. Then add about 2 lbs of pH increaser, for each gallon of acid used, and refill the pool.

  54. We bought a pool in 2016 not even a year into having the pool we noticed rust seeping out on the deck as well as inside the pool. We told the company they sent out the company who they contracted to do the work came out and cut out a piece of the concrete from the deck and cut out a piece of the rebar and did a crap patch job and used CLR to Scrub the rest of the rust away which didn’t work by the way. Well here we are almost 2 years later and they just came out yesterday to do another crap patch job on another spot that had bad rust and tried again with the CLR but it didn’t work again, so I guess my question is what should we do? Since we have pretty much been getting the run around should we file a law suit? I just feel if you spend that much money on an inground pool and have as many problems we have had right away after the pool was inslalled is all red flags and something needs to be done.

    • Hi Leslie, to see rust coming out of the concrete pool deck and pool surfaces is disconcerting to say the least. I can imagine your frustration and anger. The cause of it could be that the reinforcement steel or tie-wires used to secure the rebar, is too close to the surface. It should be beneath 2″ of concrete. The concrete could also have been mixed, applied or cured improperly, allowing water to come in contact with the steel. In either case, such areas will continue to occur, in those affected areas. Document everything, just in case you have to go to court. Hopefully the builder will fix the problem to your satisfaction before it gets too that point. You may need to clearly express your dissatisfaction – and your intent to file suit, if the problem is not ‘erased’. You shouldn’t have to accept this with a new pool. And CLR? Won’t fix the problem, just helps remove rust. Muriatic acid may do a better job, but again it just removes surface staining, does not fix the problem, of rust – from the inside-out! Good Luck!

  55. Hi, I’m new to having a pool so I have a few concerns about it don’t want a pool company taking advantage of my ignorance. So my pool water is clean to the eye however I know the water chemicals readings are unbalance and the technician recommends to drain it hes saying the CYA levels is very high level so draining the pool is not an issue to me, but he’s also recommended to acid wash it. As I mention The water in the pool is clear blue I don’t see any algae or harsh stains on the plaster. What should I do ? Pool is getting drain Right now. I don’t want to do something that’s not necessary at this time but don’t want to sound as if I’m being cheap as that is not the case and I don’t want to get taken advantage of it either. Will a simple scrub work ? What do you recommend ?

    • Davy Merino

      Hi Mari, acid washing is done to improve the appearance of the plaster, if it is dull with all-over light staining, or if there are spots and stains, or a bathtub ring. But if the pool surfaces look good to you – tell him not to acid wash it. Especially if the real purpose of draining is just to lower the CYA levels (and TDS and other water-choking contents). Acid Washing purposely strips a thin layer of plaster, and can roughen the surface slightly, so it’s best NOT to do it, unless you want to improve the appearance. Good question, thanks.

  56. Hi recently bought a house with a pool. (In Las Vegas and vegas has harsh water) It had the original pump and worked great-crystal clear water and plaster. Needless to say I work out of town and my pool guy went mia as well has the pump broke and by the time I got home my water was green. I hired a new pool guy to acid wash it and service it weekly along with buying a much larger more efficient pump. About a month after it was acid washed there were huge orange stains not only on the bottom but on the walls of the pool..pool guy shocked it, nothing happened then put a stain remover in it still nothing then put yellow treat in it..still nothing then put another stain remover (not sure what it was) an ran the pump for 48 hours straight on high…still nothing I have noticed there are cracks at the bottom now in the plaster and the stains are all still there..pool guy said there’s nothing that can be done unless we drain again and re acid wash or the plaster. Please help as I am so upset and not sure what caused this to happen.

    • Davy Merino

      Orange, huh? Typically red-orange stains are iron based. if so, there should high iron content in the water still. You didn’t mention trying to sequester the stain back into solution (not sure what ‘stain remover’ was used. Might be a long shot, but balance water, put pH around 7.0-6.8 and add any Stain & Scale treatment like Metal Free or Stain Away. Brush, and if you’re lucky it might be a cheap solution. You could also test the water for iron with iron test strips. Another solution is to use a jandy Stain master over the areas, to acid wash the surface, but underwater. Attaches to pool pole.

  57. Michele Groenewald

    We filled out newly white marbelite pool last night. Yesterday it rained and in the shallow end there are muddy spots on the marbelite. We tried brushing and it doesn’t go away. The pool is halfway full so we are carrying on filling today.
    How do I get those marks off on new marbelite? I have a suspicion a child went into pool yesterday and with muddy feet made those marks.
    Will the marks come off new marbelite and what can we do. Desperate please

    • Davy Merino

      Hi Michele, chances are that they will fade away. I would wet the area, then sprinkle some granular pool shock chlorine to the area (now), or maybe Comet cleanser, then brush and rinse well. If that doesn’t work, you can try a stain remover like EZ Stain or A+ Stain remover, but when water covers the areas. Keep filling the pool, and brush it 2x daily… good luck!

  58. Hi I have a salt water stone pool. I believe its all stone, its taken us a long time to learn the care of one of these pools. (Never had a pool before)we clean it use shock and check the pH levels.
    It’s been very hard keeping it clean and clear because the trees around it.
    Our question to you (because no one can answer us)we have a black and white stain on the outer rim at the water level. We seemed to try everything but sadly no luck. Please HELPPPPPPPPP

    • Davy Merino

      Hi Donna, water level stains, or bathtub rings, are normally a mixture of dirt, oils, minerals and other stuff. Enzymes are often an effective preventative treatment, especially for oil based rings. If it is more scaly and flaky, and not very oily, you may want to try muriatic acid, diluted 50/50 with water and poured on the wall to see if it bubbles up and scrapes off. Stone pools also can develop efflorescence around the water line, but this is calcium and other minerals leaching from the backside of the pool wall, from water outside the wall, leaching (seeping) thru the mortar. This can also be removed with careful acid washing, a pressure washer can also be used (separately from acid washing), to remove many types of water line stains and scale. All treatments require lowering the water an inch or two, so you can really get at it… good luck!

  59. Orsymco Rodgers

    My problems started when my pool heated sprung a leak. After replacing the heater I was told not to turn it on until I got all the chemicals balanced. So I had to raise the PH level, raise the Calcium Hardness and lower the Cyanuric Acid/Stabilizer. And after taking 3 feet out of the pool and putting new water in the levels were find on Thursday. Then this past weekend my steps have a black stain on my. Today Monday the white cover around my pool lights have a grey film on it. What happen? The water is crystal clear and all the chemical are showing good.

    • Davy Merino

      Hi, sounds like some metals and/or minerals got knocked out of solution, mixed with dirt and deposited themselves – black and grey stains could be copper or silver, but is likely a mix of many particles. It could have happened if you shocked the pool, perhaps the fill water has high metal or mineral levels. Sometimes such stains fade and disappear again, quickly – but if not, use a sequestering agent like Stain Away or Metal Free to try and absorb the metals back into solution. Then you have to add maintenance doses to keep it active, because it degrades in 1-2 weeks time. Pool Rx may also be a good solution to try and remove some of the metals from the water. If you do have high metals in your fill water, consider also using a Pre-Filter when filling the pool or topping off, to remove metals and minerals, or fill from pre-treated home softener system water. Another treatment is to use our Stain Removers like EZ Stain or Stain Free to hit the spots affected.

    • philip van Bosch

      Will it help if I paint over the spots

      • Davy Merino

        Hi, yes aside from acid washing a plaster pool, another good way to get rid of pool stains is to just paint over them. Of course you have to paint over the whole pool, or you get a ‘reverse stain’, where there are lighter/cleaner looking ‘stains’. Same thing sometimes happens with using a stain bag or stain master tool, you have to ‘feather’ the stain removal just right, and be precise enough not to end up with a bunch of small white(r) circles around the pool… 🙂

  60. Hi, I have a big dark brown stain at the bottom of the pool just below the steps . The rest of the pool is fine. This is a
    plaster pool with a salt chlorinate. The pool man has tried shock treatment and the other tricks of the trade (no idea what he used) . The stain has been there for a few years and doesn’t appear to be getting bigger. Could it have been caused originally from salt (20kg bags) poured in from the steps? Your advice would be appreciated. Thanks .

    • Hi Angela, adding salt in a single area and not brushing it could cause stains, but usually requires a high pH level at the time, and may also require salt that has impurities, such as solar salt or mined salt that is not purified to remove metals. The typical tricks of the trade are 1) Chlorine, will remove most organics, 2) Acids, will remove most metals/minerals and 3) Sequestering agents, which will absorb suspended metals and minerals in the water, to keep them in solution (to keep them from staining), but may have little effect on stained surfaces, or metals that are already precipitated and deposited. If the area is extremely rough, and the plaster very thin in that area, what you could be seeing is the gunite (concrete) below the plaster, showing through. Not sure if you’ve tried to acid wash the area, but that might be the next step. The Jandy Stainmaster is a device that can deliver liquid acid (muriatic) directly to a source. When placed flat on a surface, a small valve opens to release acid inside of a 3″ diameter cup, attached to your pole. It is very time consuming for large areas, but can handle a few square feet if you have a few hours time. But if it did work well, you may want to drain the pool, at least to below the stain, acid wash the walls and steps and floor area exposed, and then refill, rebalance, and add more salt (to the deep end, with the main drain on Full, and using a brush to push it around). Also have the pool pH in the 7.2-7.6 range before adding salt, and be sure that it is Pool Salt, or Food Grade salt, which go through brining and evaporation to remove impurities like iron, copper, manganese, and contains no Iodine, like some table salt.

  61. Kathy Wesselman

    We are sick to our stomachs. After playing over $3,000 for a new liner, $400.00 in chemicals to get the pool started back up, the entire liner is green. Been to two different pool stores for solutions and multiple hours of putting in different combos of chemicals, still green, no change at all. Brush scrubbing does nothing. Now what?

    • Hi Kathy, your blue liner has turned green? That’s a new one – I suppose it’s not algae, or algae stains, but I would copper? High levels of copper, with a high pH, can drop out of solution during a shock treatment. If you havent’ tried a sequestering agent, for metals, I would add MetalFree or Super Stain Away, following instructions closely. You can also test the water for the presence of metals, to see what you are dealing with. Jacks’ Magic products has a Stain ID kit and Stain Solution #1, the Iron/copper Stuff that is effective on metal stains. Vitamin C (ascorbic acid) can also often be effective. You can test with crushed up Vit C tablets, and treat with Stain Free

  62. Sharon Whipple

    This year our pool has a stain all over this year. yellowish/green. It was a mild winter and was told algae may have taken over the concrete. I have well balanced water but I am lost. Jacks stain kit did nothing. Vitamin C test left a little orange stain but no removal. It has been 6 weeks. Plaster feel a little rough. I have scrubbed with a metal brush- no luck. Pumas stone took some off the easy areas but I can’t do the entire pool with a pumas stone. I know that wear away the concrete also. someone suggest Jacks, Iron Cobalt and etching but when I called Jacks for details they said if the stain kit didn’t do anything not to waste my money. I really believe it’s organic due to the color and winter conditions.But High chlorine didn’t help either. any further ideas?? Thanks.!

    • Davy Merino

      Hi Sharon, what can sometimes happen is a film of calcium carbonate can settle over the surfaces, locking in algae. Try lowering the pH to 6.5, using a nice test kit like the K-2005 that can do an acid demand and base demand… broadcast pH decreaser over the pool (granular) then brush hard with a steel bristled pool brush, 3 times if needed during one day. If you have a heater or salt cell, leave the pump off for the day (make sure chlorine is a little extra high the morning of…) so the low pH won’t cause problems. If that doesn’t do the trick and remove the stains, you can try EZ Stain Remover, a mild acid granular that is sprinkled over the area.

  63. Richard Koster

    Hi. A small metal washer sat on our fibreglass pool bottom for a couple of days and left a rust stain. How can this be removed?

    • Hi Richard, you can make a stain sock – fill an old orphan sock (thin, or hosiery), with pH decreaser, or even better, Super Stain Away, with 1-2 cups of chemical, in the sock. Tie the sock off tightly, and cut off excess sock above knot. Push it down on the stain with your pool brush, and hold it there for 30-60 seconds, then remove. Place again if you need more. If very severe, it may need several treatments, but don’t leave it for long, as you may get the reverse, a larger white spot, lol. There is also a device called a Stain Master, which delivers muriatic acid or other liquid acids, thru a hose, directly to a small (3″ dia) cup placed over the stain. Move it around so it won’t over-acid any area. Finally, you can sand the stain with wet/dry sandpaper, to reduce or remove the stain.

  64. We have a new pool so therefore a new well water fill.Ive adjusted the PH.Since it’s well water, it’s copper colored, but because the filter has been running all day, I can see the bottom…barely. I’m wondering if I should add the stain out now, or after I add the chlorine.I think the chlorine cleared it up last year, but not sure.I will add the chlorine towards dusk.Thanjs for your input!

    • Hi, best practice is to use the Stain Away (or other sequestering agent), before adding the chlorine, even during the fill is OK. High levels of chlorine from shocking can deactivate the metal control chemicals, or cause metals to drop out of solution, if not previously treated. If you have shocked the pool already, no problem, after the chlorine level drops add your initial treatment of Stain Away, and then add regular maintenance doses, every week or two, to keep minerals tied up in solution.

  65. We have a yellowish sticky stain around the inflated top ring of our vinyl swimming pool. We do not leave the pool up during the cold months. This appeared last year after setting up the pool for the summer. Pollen? What would be a safe cleaner? We tried hot water and lots of Dawn dish soap. Did not work.

  66. JOHN SAGER

    looks like a brownish/yellow stain. all in the deep end where debris lays over the winter. first 3 years running chlorine high for three weeks would get rid of them. not any more. brushing, shock, high chlorine levels do nothing. now stains are popping up all around where they never used to be and it’s june in pennsylvania.

    put an acid test bag of Stain Treat (oxalic acid ) and it removed the stain completely (along with some of the plaster color)but who cares, white is better than brown,

    so i bought two containers of this stuff to sprinkle all over the stained areas and it didn’t do much. seems like the the stuff works (a sequestrant & chelator ) but has to be very concentrated. i guess i have to buy around 30 little bags of the test bag stuff and put directly on the stain overnight…. the little bags cost $8.00 but that’s better than emptying the pool to acid wash.

    why are all these little brown stains appearing everywhere over the last two weeks for the first time ever?

    chlorine is pretty high and ph is a little low.

    please advise.

    • I’m not sure what the stain may be from, but it’s usually animal, vegetable or mineral. Most organic stains from leaves, worms, bird droppings, tree debris or berries will remove easily from concrete pools with high chlorine. Mineral scale however, takes an acid to dissolve it. Your stains may be a form of calcium or magnesium scale, mixed with dirt, algae, or leaf tannins. Check your pH level often, especially if your calcium hardness levels are higher than 200 ppm.

  67. Kristen Pennachi

    Hello. We bought a foreclosure that had a mostly drained pool with leaves on the bottom covering a very BLACK stain . The pool then sat for 4 months collecting rain water and other debri . There was even a bicycle chain laying on the bottom. Countless bugs,Centipedes, glass, organic material , etc. we drained and acid washed it. Some stains came out but the chlorine bath was the best. It removed most of the stains on the entire pool except where the black stained were and the water and leaves from before we bought the house. The black stains are now brown dingy stains. We have repeated this process with 20 gallons of chlorine . Spraying a gallon a day. I think it’s done working now. We are still left with the stain. We don’t know what else may help. Also when we sprayed chlorine it would dry and create a reddish pinkish powder that we could wash away. When we soaked the stain with 10 gallons of chlorine for three days… before we decided spraying and letting in dry was better… the chlorine that was soaking turned bright pink. Don’t know what to do. Need to fill it soon . Advise would be GREATLY appreciated ! Thank you ! I will send pics .

    • Hi Kristen, you may never remove all of the stains, I think you’ve made a good effort thus far. They will lighten once you fill the pool and shock it, but they probably won’t completely fade away. Go ahead and fill the pool, balance the pH, Alkalinity, Calcium Hardness levels to normal pool ranges, and then shock the pool with a heavy dose of pool shock, sprinkling over the stained area. Brush and vacuum pool. After chlorine comes down, recheck the chemistry and add a Sequestering agent, aka “stain & scale” chemical like Scale Free or Stain Away to lock up iron or other metals and minerals, in solution. Add a maintenance dosage of metal control each week, because it breaks down in 1-2 weeks, or after shocking.

      • Try vitamin C tablets (ascorbic acid) over the suspected rust stained areas. Tie a few tablets together in a thin piece of fabric and let it sit over the stain for like 15 minutes – filter off. If this lightens or removes the stain, then it is rust.

  68. Michael Chidiac

    I have stains caused from shock sitting in place for a long time. My cleaner did not turn on for a couple of day after I added shock. The shock ended up on the bottom of the floor of our gunite in-ground pool and left white blotches. How do I get rid of them?

    • Hi, I guess what you have are ‘opposite-stains’, or where the area where the shock laid, is now bleached a whiter color. Not much you can do about that, except for perhaps a repeat treatment over the entire pool, or a drain and clean (acid wash) of the surface. But if you do check that water balance is correct, and some heavy pool brushing – may have some small effect.

  69. david boozer

    I have black and whiter stains on my plaster from someone throwing chlorine tabs on to the bottom of my white plaster, what can be done to get my plaster back to normal, looks like hockey pucks all over the place, and one 3ft by 3ft spot where it looks like it was sliding around.

    • Davy Merino

      Hi, well those stains are pretty difficult, as you probably already know. I would start by keeping very good balanced water, and then you can buy a device called a Jandy Stainmaster, to do localized acid washing, with a gallon of muriatic acid, bought locally at the hardware store. That won’t remove it completely (well, it might), but it’s the next best thing, short of draining and acid washing. You could also try some other methods, such as filling a tube sock with granular pH decreaser and placing it over the stain, moving it after 20 minutes or so with a pool brush, it will have less of an effect than putting acid directly on the stain. Unfortunately this is a type of stain that may be difficult to remove completely.

  70. Alicia Sylvester

    Hi just bought a house with a pool. The bottom is full of black and dark gray patches. I used no phos but it’s still the same. I think is a metal stain all over.
    What can you suggest

    • Hi Alicia, I would recommend draining the pool and acid washing the surface, and refilling with fresh water, balanced to good levels. If the pool surface is that bad, I would bet the water quality is also poor, and it would be easier for you, to start out with fresh water. Plus, serious staining pretty much requires draining and cleaning. Unless this is a vinyl or fiberglass pool you have – then acid washing is not an option…

  71. Hi, I recently drained out my pool as there was alot of sand at the bottom. The walls are stained a bit. If I acid wash the pool, I was told that it would be rough, if I have to paint the pool with a few layers would it then become smoother? I might use an epoxy paint.

    • hi there – acid washing can make a surface rough, but it doesn’t have to… if you use a weak solution 1 part acid, added to 2 parts water, applied to moist surface, and rinse quickly after pouring over the surface from a watering can, the erosive effect is very minimal. But if you use straight acid, and let it burn for a minute or two, it will continue to erode, until it is diluted and rinsed. Acid washing is a purposeful stripping of a very thin (1 mm) layer of plaster, to expose fresh, unstained plaster beneath. It doesn’t necessarily make the surface rough, if you do it right. This includes the strength, the burn time, and controlling the acid/water run-off, by diluting and spreading it, to prevent acid/water wear paths on the floor, or at the end of steps, where the acid/water is rinsed off. Rinse randomly and profusely – and keep all surfaces wet. Start with a weak acid/water mix, in a flower watering can, for the first gallon. You can increase the strength if needed.

      Rough patches in plaster can be sanded with a rotary grinder or sanding blocks. Pool paint will also make a rough pool surface much smoother, and epoxy pool paint is the best type of paint to use in most cases.

  72. Alexandra Liebler

    I had a bunch of pool stains from little seeds from my Royal and Queen palms and i brushed and brushed and they didn’t go away. Then I tried putting a chlorine tablet on the stain and waited about 10 minutes and voila absolutely removed!!! It acted like an eraser. I moved it to the next spot and it removed the stain. I did it for about 20 spots in my pool and they all disappeared. It was so simple I hope it helps someone else too.

  73. Maureen Heath

    Can a pool be acid washed more than once
    Thanks

    • Hi, yes it can, every few years it’s not a problem, if done gently! Acid washing is a purposeful stripping of the top 1/16″ of the plaster, exposing fresh plaster underneath. Aggressive acid washing can damage plaster and frequent acid washing will wear it thin. Plaster can be only 3/8″ thick in some spots, although it can be much thicker in other areas. So if you acid washed it every year, even gently, after about 10 years, the plaster would be worn away in thin spots exposing the plaster beneath. However, if you acid wash (gently) every 5 years, and replaster every 20 years, you should have no problem.

  74. Maureen Heath

    My pool was resurfaced 15 years ago and acid was about 8 years ago. A few years later copper got into the pool and the side have black stains in places. My pool guy said that the pool couldn’t be acid washed again so it has been left. Is my only option to have the pool resurfaced again
    Thanks

    • Hate to disagree with your pool guy, but copper stains can be removed from plaster. In cases where copper stains are very heavy, it can be difficult to remove all staining completely, but in most cases, an acid wash will remove all copper staining. A third option is to embrace the stain, and learn to love the abstract beauty! If you want, add more copper, silver, iron, and use the pool as your art palette! 😉 I’m joking, but to some people, the usual blue/green copper stain is not too objectionable. Black copper stains aren’t as pretty however.

  75. Will acid washing a pool restore its color? My pool used to be a beautiful blue, now the color has faded. If not, what are the best options to bring the pool back to life?
    Thanks,
    Penny

    • Hi Penny, an acid wash is the solution to restoring colored pool plaster’s deeper colors. What happens is that a layer of calcium scale and other white-ish deposits onto all plaster pools. On white pools, you just don’t notice it. But on a colored pool the mineral layer can look undesirable in some cases. Acid washing with a mild solution 3:1 should remove a mild deposit. Heavier deposits may need a stronger mix or a secondary acid wash, to remove all of the deposits. It must be done carefully and gently, to avoid too much corrosion of the plaster. Ideally, you want it just strong enough and to sit just long enough, to eat through the scale, but not too much of the plaster beneath. After acid washing, refill the pool using a pre-filter on the hose, balance the water carefully, and try to keep it that way, while also using a stain & scale product like Stain Away to keep mineral scale from forming. If you are wondering if pressure washing is an option to an acid wash, it is, but it won’t work as well, and will take 3x as long.

    • Thanks so much for the information, it is most helpful.

  76. Hi, I would like to ask if you have come across black spots on the surface of the pool lining. The lining is Quartzon and only 4 months old and the pool is mineral. The black spots don’t have a head as I have tried to scratch them off. The water balance is normal and I have kept the water slightly acidic in hope the spots will go away. Thoughts?

    • Hi Tim, black stains that are not calcium crystals or black algae, could be mineral staining. If your pool uses a power ionizer, staining can result from overuse – copper and/or silver staining. Cobalt or manganese in the fill water can also produce dark spots, or it could be rust, from accidental metal shavings or pieces getting into the pool. It could also be stains from berries or tree nuts or animal waste – these will remove easily with chlorine shock sprinkled over the stain. If that doesn’t work, you can try sprinkling Stain Free or use a stronger acid like Stain Away over the spots. If that doesn’t work, draining and acid washing the Quartzon (a type of pool plaster, for those that don’t know) to remove the stains.

  77. Tania Wells

    Had pool acid washed and then painted. Now black spots are showing up. What can I do to fix this?

    • Hi, must be frustrating. Black spots you say? Could be Black Algae, lets just throw that one out there right away. If you inspect it closely (underwater with a mask), you will be able to tell if it’s algae, even if it won’t brush off easily, it will scrape off. Now it could also be metal staining, minerals such as manganese, or copper can make streaky black stains, maybe dots and spots, too. Thirdly, you could have stains from berries or acorns, or something – these would lift immediately with granular chlorine sprinkled over top, and a light brush. If shock doesn’t do anything, you can try crushed up Vitamin C tablets, and if that works, you could use Stain Free Ascorbic Acid stain remover. If neither of those works, you could use one of our Stain Away chemicals. But first, make sure that it’s not algae, and be sure the water balance is perfect, and that you are filtering and sanitizing and cleaning properly. Hope that helps, Good Luck!

  78. Hi, i would like to ask if how to remove the black or grayish line above the water level of pool around the wall? Thank you

    • Hi Ryan, using enzymes regularly can help control oily deposits and prevent waterline staining. Most waterline deposits are a mixture of dust, calcium, oils, etc. When calcium is very high in hard water, a white-ish scale can form at the waterline. Black or Grey-ish, you say? Try to see where it is coming from, (mulch, pollen, dust, auto/plane exhaust, oils, grease, soil).

      If you have TILE, you can lower the water level a bit, and scrub it clean with small amounts of abrasive cleanser, like Comet or Bon Ami. Use a textured sponge and apply pressure. This is easiest done inside the pool, in most cases. If there is scale deposited on the tile, you can add a cup of muriatic acid to a spray bottle that already has 2 cups of water inside. Wear goggles and gloves and spray over wet calcium scale, then scrub it with a brush, or scrape it with a putty knife, then splash off the acid with pool water. You can adjust the strength of the acid as needed.

      If you have VINYL, you can lower the water, but you don’t want to use anything as strong as acid or chlorine. Natural Chemistry makes a good enzyme based pool cleaner called Clean & Perfect, or use a pool tile and vinyl cleaner like, we have two – regular and ‘super’, which is more concentrated. These are mild enough to not harm vinyl liners, but strong enough to remove most waterline deposits.

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