Cloudy Pool Water Issues

cloudy pool water issues

As a former pool store manager for over a decade, you can trust that I’ve heard my fair share of, “My pool water’s cloudy, what can I do?!” In fact, it was the number one issue, day in and day out. It was my job to figure out what was causing the cloudy pool water and how to fix it.

What Causes Cloudy Pool Water?

What Causes Cloudy Pool Water?

Unfortunately, there are a number of reasons why pool water goes turbid. Truthfully, it’s not uncommon to find the water a little hazy when first opening the pool each spring. It will sometimes pop up again during swimming season if conditions aren’t right. Water chemistry, circulation, and filtration are the most common culprits when it comes to cloudy pool water problems.

But one thing is for certain – when your pool turns cloudy or milky blue, you need to find the source of the problem and fix it right away. Cloudy water is just one visible symptom for a number of problems in the pool.

Low Sanitizer Levels

Have you ever noticed that if you forget to put chlorine tabs in the pool, it begins to turn hazy before it goes green? Without a constant supply of sanitizer, particulate matter accumulates and becomes visible, sometimes within hours!

Low sanitizer levels can cause cloudy pool water

There are three forms of chlorine measured in a pool: Free Available Chlorine (FAC), Total Available Chlorine (TAC), and Combined Chlorine (chloramines). Free Available Chlorine is the one that actually does the sanitizing; it’s free and available to fight off germs and algae in the water.

Ideally, your FAC and TAC levels should be the same, and both should be in the 2.0-4.0 ppm range for most pools. When TAC is at least 0.3 ppm higher than FAC, it means your pool has too much inactive Combined Chlorine (chloramine) in it. Break down those chloramines with a shock treatment. Pool shock can also be used to raise chlorine levels that are too low. If TAC is above 2.0 ppm, use a non-chlorine pool shock. If it’s under 2.0 ppm, use chlorinated shock.

Poor Water Balance

If any aspects of water balance move to the high end of the scale, you’re setting yourself up for a battle with cloudy pool water. Not only can unbalanced pool water lead to cloudy conditions, but it can cause problems with sanitation, as well. Keep your water within these recommended ranges:

  • Total Alkalinity: 80-120 ppm Ideal (60-180 ppm Acceptable)
  • pH: 7.4-7.6 Ideal (7.2-7.8 Acceptable)
  • Calcium Hardness: 200-400 ppm Ideal (150-800 ppm Acceptable)
  • Cyanuric Acid: 30-50 ppm Ideal (10 ppm Minimum)
  • Total Dissolved Solids: 0-2500 ppm Ideal for Non-Salt Water Pools

Inadequate Circulation

Inadequate circulation can cause cloudy pool water

Your pump and filter can only do so much to turn over all of the water in your pool. If your pump can’t work efficiently, or if your return eyeballs aren’t arranged to increase circulation in the pool, you’ll constantly be struggling to keep the water clear.

Keep skimmer and pump baskets free of debris. Ensure that there are no clogs or leaks in pool plumbing or equipment. Run the pump for 8-10 hours a day (more for variable speed pumps) or longer in hot weather. Brushing the pool, using an automatic pool cleaner, and even just using the pool will boost circulation and help move water around the pool more efficiently.

Inefficient Filtration

A filter that’s not sized correctly for a pool won’t be able to work efficiently. But even if your filter is the right size, old or damaged filter media (sand, filter cartridges, and DE grids) will allow fine debris particles to move right on through and return to the pool. As you can imagine, this is problematic when you’re trying to clear up increasingly cloudy pool water! Pump issues and air leaks can also impact filtration ability.

High Levels of Contamination

High Levels of Contamination

A high bather load, animals in the pool, and stormy weather can all bring high levels of contaminants into the water. When this happens, it’s hard for your filter to keep up. Bather waste, such as sweat, body oils, lotions, and cosmetics, will quickly overwhelm and gum up your pool filter. This is why it’s so important for swimmers to take a shower before entering the water! Add in the amount of pollen, dirt, hair, organic debris, and other pollution brought in by wind, rain, and water-loving pets, and you have quite a mess on your hands! Another source of high water contamination is a layer of fresh plaster. Fresh plaster can “dust up” for the first 6-12 months after it’s applied.

Other Causes

There are a few other ways pools can cloud up. Some are even caused by pool owners themselves during chemical applications. For example, cloudy water after shocking the pool is actually a pretty common occurrence. It’s usually just a temporary reaction, as the sanitizer works its magic, and doesn’t always indicate a problem.

But if the cloudy water persists long after you’ve shocked the pool, you’re likely having an issue with water balance, circulation, or filtration. Heavy use of a calcium based pool shock (cal-hypo) may increase Calcium Hardness over a period of time, increasing your odds of cloudy water. Other chemical application errors have been known to cloud a pool. For example, adding more than one chemical to the water at a time or using chlorine products in a biguanide pool will cause adverse reactions. 

Can You Swim in Cloudy Water?

It depends. If the water is so cloudy that you can’t easily see the bottom of the pool, nobody should be swimming in it, let alone diving into it. Severely clouded water poses an increased risk of severe injury or drowning because of the lack of visibility and depth perception. But even if the water is only slightly cloudy, it’s still not a good idea to go swimming until you understand what’s causing it. Cloudy water can harbor all sorts of germs and waterborne pathogens.

How to Prevent Cloudy Pool Water

how to prevent cloudy pool water

If you want to avoid cloudy water in the first place, it really just boils down to properly maintaining your pool:

  • Test the water at least two or three times a week to ensure healthy water chemistry.
  • Keep Free Available Chlorine, Total Alkalinity, pH, Calcium Hardness, and Cyanuric Acid levels in the proper ranges.
  • Shock the pool once a week to keep your sanitizer working efficiently, oxidize contaminants, and ensure adequate chlorine levels.
  • Run the pool pump long enough to filter all of the water in the pool at least once a day, and don’t forget to keep your pool filter clean.
  • Encourage swimmers to shower before entering the water, to avoid overwhelming your filter and sanitizer with body oils, cosmetics, lotions, deodorants, and other contaminants. This is especially true if your pool has a heavy bather load or gets used frequently.

How to Fix Cloudy Pool Water

Even under the best circumstances, cloudy pool water can still pop up from time to time. If your pool water looks hazy and turbid, follow these steps to make it crystal clear again.

water test kit

Test

pool shock

Shock

water clarifier

Clarify

  1. Clean the pool thoroughly to remove all organic debris. Clean out pump and skimmer baskets, skim the surface, vacuum the floor, and thoroughly brush all pool surfaces (floor, walls, steps, waterline, etc.).
  2. Test and balance the pool water. If your at-home test kit is old or untrustworthy, take a sample to your local pool store for more accurate professional testing. Some stores even offer free water tests!
  3. Shock the pool according to label instructions.
  4. Run the pump 24/7 until the water clears up. If your filter’s pressure gauge is 8-10 PSI higher than the starting “clean” pressure reading, clean the filter.
  5. Use either a clarifier or flocculant, which will coagulate the small particles your filter missed into much larger clusters. Clarifier helps your filter work more efficiently to remove those particles as they pass through. It’s ideal for mild to moderate cloudiness, and can be used as a preventative measure during regular maintenance. Flocculant drops the suspended particles to the floor, where they must be vacuumed to waste. Pool floc is great for extreme cloudy water conditions, and it works much more quickly than a clarifier. However, the pool floc method is more time intensive, you’ll have to replace lost pool water, and it’s not usually a viable option if you have a cartridge pool filter (unless you have a filter bypass valve).

Bonus tip! If you have a robotic pool cleaner, use it to help clear your cloudy water. Most robotic cleaners can filter particles as small as 3 microns. In some cases, they may even be more efficient than your regular pool filter. But even if you don’t have a robotic cleaner, any automatic cleaner will at least increase circulation throughout the pool and help clear the water faster.

When Cloudy Pool Water Won’t Clear Up…

Stubborn cloudy water issues are a pain! If you’ve followed the steps above and your water still has a hazy appearance, there are a few more things you can check.

As we mentioned earlier, take a good, hard look at your pool filter. Does it need new filter media? Age and consistent use eventually take their toll, and your filter loses its ability to capture smaller particles as the media wears out. Also consider if the filter is sized properly to accommodate your pool and support the flow rate of your pool pump.

If your filter pressure is lower than normal, there may be a clog in the pump impeller, pump/skimmer baskets, or elsewhere in your plumbing system. Another possibility is a faulty backwash valve. Check to see if there’s any air entering the system, and either refill the pool to proper levels or address air leaks as needed.

Check that your pump is operating correctly. Make sure the motor is not overheating and cycling on and off. If the pump isn’t circulating for long enough each day, your filter can’t do much to help clear your pool water.

A Quick Note on the Langelier Saturation Index

Developed in the 1930’s, the Langelier Saturation Index is a handy way to calculate your pool water’s propensity to scale, or precipitate calcium and other mineral salts. Negative results indicate a corrosive water propensity. The formula can be used to determine if the water is dissolving, precipitating, or in equilibrium.

The formula is: pH + AF + CF + TF – 12.1

AF = Alkalinity Factor
CF = Calcium Factor
TF = Temperature Factor

How do you find the “factor?” Refer to the chart below to find the appropriate number based on conditions in your pool:

Langelier Saturation Index Chart

A pool in perfect equilibrium has a result of 0.0 – yet anything from -0.3 to +0.3 is acceptable, and considered to be neither scaling nor corrosive.

Performing a saturation index calculation can help you see how to adjust your water balance to avoid scaling water conditions, which lead to cloudy pool water. Pentair has a nice Saturation Index calculator on their website, if you’d rather not do the math!

The Index incorporates water temperature into the calculation, which plays an important role in water clarity. Ideal pool water balance fluctuates from spring to summer to autumn, because of the effect of water temperature on dissolved solids.

79 thoughts on “Cloudy Pool Water Issues

  1. Shantell

    Hello,
    My pool water is very cloudy after adding 7 pounds of Soda Ash which is what the pool store said I needed after taking water sample in. My pool was very clear before adding this I mixed the Soda Ash with water before adding to pool. Will the cloudiness go away on its own or do I need to add another chemical.

    • Hi Shantell, soda ash (pH increaser) can sometimes cloud the water, that’s normal. It does go away, as long as you run the filter a little extra, and keep good water balance (re-test that pH and chlorine). If it’s taking awhile, you can use a Clarifier to help the filter out.

  2. Maria Duke

    Very cloudy water & then white sediment to pool sides & bottom— being blown out of pool outlets when “new” Hayward EC65A pump is first started. Pump Troubleshooting steps done & is still blowing out very cloudy water for first 60-90 seconds.

    • Hi Maria, that could be either holes in one or more of the fingers, the “Flex Tubes” that keep the DE powder in the tank. Or it could be a missing E clip on the bump shaft that holds the top and bottom plate together, or a missing nut/screw that also hold the top and bottom plate together.

  3. Hi, I shocked my pool 10000 gallons with 1lb of shock straight away it went milky, the pump has been running now for 36hrs it is slowly clearing. Did I use too much shock ?

    • No that’s not too much, that’s a regular dose. It could be shock residue or could be that the shock knocked out carbonates or calcium out of solution. Use a Clarifier if needed.

  4. Lisa Serrano

    Hi Davy,

    My pool water was a very light green last week we put de-mineralizer in it and it immediately turned blue cloudy. It was very milky looking so we added shock to it and kept 2 tablets in it the next day it became a bit more cloudy then milky. I have been cleaning the cartridge daily and running the filter 24/7. I was starting to see the bottom of the pool and the ladder. I have also been draining the water up until under the skimmer and refilling. I would like to mention that it is a summer waves pool and i have connected an intex 2500gph filter to it. My pool has 5500 gallons. I vacuumed yesterday and added a little clarifier but its back to being cloudy again. I dont know what to do.

    • Hi Lisa, I wonder how old the filter cartridge is? If older than 90 days, replace with new. Intex actually recommends every 30-days, but that’s a bit much I think. Be careful not to over-dose with clarifier, that can cause an opposite effect. Shocking the pool again might be helpful.

      • Lisa Serrano

        Hi Davy,

        I put in a new cartridge yesterday both for the intex and for the summer waves filter. I think I put too much clarifier honestly. I am at the verge of giving up. Do you think I should drain and refill? I should mention I initially had it up and the water was sparkly clean and I took it down to relevel the ground. As it was filling up the second time, the water was a very very light green and I can see the ground of the pool and everything. When I put the de-mineralizer in thats when it turned a blue cloudy color. What should I do ?

        • I thought your name sounded familiar! Too much clarifier can do that – act as a dispersant, instead of a coagulant. Shock will break up the clarifier polymers, or destroy the charge – so you could shock it really well, and keep filtering, might take awhile, or (if it were me), you can drain the pool, or 90% of it, and refill. Since your pool is so small, I would drain it. Normally do not recommend that for cloudy pools over 5000 gals. As i like to say “Water is cheaper than chemicals!” – or in most cases it is anyway…

  5. Steve Drake

    Hi , was told my ph level was low and advised to add ph increaser. Now ph is 8.1 and pool is cloudy and can’t see the bottom ( above ground pool ) .will using the pool help clear up cloudy problem and would it be safe to swim in ?

    • Using the pool can help circulation yes. It would be safe, as long as there is a good chlorine level. All you need now is an acid, dry or liquid, to lower the pH into the 7.2-7.4 range where chlorine is most potent. Resist the urge to raise pH from 7.2, that is a good place to be…

  6. Laura Silva

    Ok today when I took the filter out it looked green so I put a brand new filter in even though it was a new filter. Was is it still cloudy and the filter is green?

    • How is the chlorine level and the pH level? And are you running the filter 24/7? Small filters, like those used on Intex pools, are just barely adequate, especially the ones that come with the pool, so run it 24/7, and replace the cartridge with new every few months. Also helpful with these filters is using weekly doses of algaecide and clarifier.

    • Laura Silva

      So this morning I changed the filter cartridge and it was a little green. I’m running my filter 24/7 and ph is ok. This afternoon it’s starting to look light green. What should I do?

      • Keep checking the chemistry, low pH – high chlorine. Keep running the filter non-stop, in short, just keep doing what you’re doing!

  7. Laura Silva

    Put the clarifier in last night and the chlorine is being kept up but no changes. Cleaning the filter 2-3 times a day. I forgot to mention that prior to the pool becoming cloudy my husband put a 1/2 a bag of baking soda in the pool. We noticed bubbles on the pool surface and immediately began cleaning the filter 2-3 times a day. I also set up a new pump/filter system. The pool is still looking the same today. I also have a clear water kit 1 bottle is a 4 in 1 treatment in which it claims it clarifies water, prevents oil & scum deposits, prevents metal stains and improves filter efficiency. Should I try some of the 4 in 1 treatment?

    • Hi Laura, hold off on the 4-in-1 for a few days, since you just added Clarifier, which the 4-in-1 primarily is also… over-dose of Clarifier can have the opposite effect! :-0

      • Laura Silva

        Was wondering if my husband putting the 1/2 bag of baking soda caused the cloudy water?

        • Probably not, although it could be a contributing factor. Normally carbonates dissolve quickly and easily, and it should not be the cause, unless TDS was very high, very very high!

  8. Pool is cloudy and tested water. FC was 0 so I shocked it and retested the water Fc is high and pool is still cloudy. Have a brand new filter system. What should I do next?

    • Laura, make sure the pH level is good and low – 7.2-ish, keep chlorine high, and run the filter non-stop. A small amount of liquid Clarifier can help.

  9. Hi!
    Had our water tested and were told our water was near perfect and the only thing out of line was the phosphates, super high after a rain storm. Pool store recommended a no phos additive. We did (only 1/2 of the recommended) and now the water’s cloudy and it actually got hot. Pump has been running almost 5 hours and its not clearing up, but the water is cooler.
    We have a larger pump (633T) and the salt water chlorinator for 15’ round 48” deep pool.
    What am I doing wrong.

    • Michele, that is a byproduct of the Phosphate removal process, the pool store should have made mention of it. Run your pump non-stop 24/7, do not shut if off at night. It will not blow up I promise. Use a Clarifier if not clear after 3-4 days.

  10. My pool is 18×24 I have tried everything to get the water clear. I recently used hth blue to green and it’s left it cloudy and not clear. I’ve tried a floccuant and nothing. I have vaccumed and siphoned out half the water. All my water chemicals check out good. I don’t want to to drain it. I have a cartilage filter that came with it. I do not live close to a pool store to take a sample of my water to.

    • Shannon, are you running the filter non-stop? Is the cartridge new? Is the chlorine level constant and consistent? Have you tried Clarifier?

  11. Lisa Smith

    It is an upgraded pump that works for bigger pools than this one. You still recommend draining it?

    • Oh, well that is good, if you think it can handle it… or how about a compromise, drain half and refill? Should cut your clean-up time and chemical expense in half? 🙂

  12. Lisa Smith

    Hi. This is my 2nd season with our Intex 15×48 above ground pool. When we opened it the pool looked like a swamp. When closing it, we drained it past the intake/outtake. Wo I filled it put algaecide in shocked it used floc and put clarifier in. It turned blue but not clear. Then it became so cloudy that it looked almost like milk. I have drained 1/3rd of the water out and filled it again. Shocked it and put clarifier in again. Chlorine level is high but everything else is balanced. The water is still very cloudy. I just figured out how to use the vacuum and did that too but it’s extremely difficult to vacuum what I can’t see. I’m just blindly going over the bottom of the pool. I’m at a loss. The pump is brand new and we change the cartridge one-two times everyday. Im spending a fortune on chemicals and filters. Im to the point that I’m ready to drain all the water out and start over. I don’t want to do that but I don’t know what else to do. If the water cleared up I’d be able to effectively vacuum the floor. Please help before I RIP my hair out

    • Hi LIsa, the filter system that you probably have it small and struggling with the amount of solids in the pool. Yes, I agree, you should drain all the water out and start over. And next year, do the same thing, right from the start. Intex filters can keep clear water clear, but they can’t turn around a swamp.

  13. I have balanced my pool used clarifier but pool is a bit cloudy and steps have yellow spots. Pool guy told me possible pump damage but I just purchased new pump last year. Filter seems to be running properly. What would cause this? Should I try a filter wash as I gave a huge tree that hangs over the pool and it’s quite a lot of work when opening.

    • The yellow spots could be yellow algae, or possibly could be spots from tree debris. Try to sprinkle some granular pool shock over the area, and brushing.

  14. SALINA BROWN

    We opened our pool this past weekend which is later than usual. WhenI first uncovered, it was extremely swampy so I brushed the sides and bottom while running the pump and then we poured 20 gallons of liquid chlorine in the pool as well a clarifier and algaecide. The pool is a 25,000 gallon in ground pool. The vinyl liner was replaced last year as was the pump motor. We also took the sand out of our sand filter and replaced it with glass. So once the chlorine was in the pool turn a blue color but it is still super cloudy so we checked the levels and the chlorine was down but ph and alkalinity were both high. So we brought the ph down and added more chlorine and clarifier and have been regularly backwashing and rinsing. We have a robot that cleans the pool so it’s not really anything on the bottom or sides but it’s still really cloudy. Any suggestions?

    • SOunds like you are doing all the right things, Salina. Only the algaecide was likely destroyed by the chlorine. What can be effective is to add algaecide and let it filter overnight, then lower the pH to around 7.2, and add the chlorine. No matter, next time. So just keep on with a high chlorine level, low pH level and add clarifer once per week (not more often), and if you can sleep, run the pump 24/7 until it’s looking better. A Sand Filter Cleaner chemical would be a good idea after the clean-up.

  15. Glenn Gribble

    Davy,
    I have had a cloudy issue since last fall. I could not see the bottom even in the shallow end for August and September. Gave up and closed an outherwise chemically balanced pool for the winter. Opened this spring with the usual green stuff which cleared up within a couple days after shocking. Still cloudy 2 weeks after opening even with new sand. I reacted and now my chlorine is greater than 10 but still the same cloudy. All chemicals seem in balance. Help

    • Hi Glenn, I would suspect that either the filter is not being run long enough each day, or the filter is undersized for the pool, or the filter (or valve) is bypassing water back to the pool unfiltered, or some combination of the three – but I’ll bet you have a filtration problem, not a chemical problem.

    • JASON Bourgoin

      Hi Glenn
      I opened my above ground pool shocked it and ran the cartridge filter with Fiber Clear filter media and it was getting clear. Already wasn’t too bad. Had the water tested added 4l s PH LOWER 6lbs. Of Zappit. 11 tabs of SunScreen tabs (For stabilizer)and I was suppose to add 1 qt of calcium hardness reducer(reading was 475). I accidentally added a gallon. The next day the pool is white as a cloud and can’t see anything. Had the pool water tested again hardness is 375 Still reads no stabilizer. They told me to add 1lb zappit again and some clarified. Pool is still white. I have been cleaning cartridge when PSI goes up 10 lbs. starts at 8 or 9

      • Hi Jason, you could add a Stain & Scale chemical, like our Stain Away or Scale Free, to sequester the precipitated mineral. The calcium reducer seemed to knock calcium out of solution, so that it became ‘undissolved’. Using a sequestering agent will re-dissolve it and lock it in solution with a chemical bond, but only if you add replenishment doses, every week or two, per label instructions.

        • JASON Bourgoin

          Do you think it will clear up fast or take along time? Would it be easier to drain and refill?

  16. Hi, I just bought an above ground pool 18*48, We use well water and I was not aware that the first thing to do was pour rust removal and I did not do that first. Actually the first thing I did was shock it with 1 lb and it a 6500 gallon pool. Now my water is orange and I have waited out the chlorine for about 2 days and it was normal so I put in the rust removal and nothing. I went to my local pool store and tool a water sample and they told me that I still had a little of iron and to put the remaining of the 1 qt of iron out inside. So I did. All this time i have been changing the filter about 3 hours each except for nights and nothing. It now is 1 week and still no change. They told me to just keep changing the filter but no results. I also added ph down due to I had high levels of alkalinity. Added 1 qt they said, and between 2 days, bottle is gone and no difference. The water is still orange but clear so I don’t know what to do I have gone to 2 local pool stores and no results. Thank you, any comment is appreciated.

    • Hi Kendal, I would suggest to try a product called CuLator, a pouch that goes into the skimmer, or pump basket, and absorbs metals. It is the only product that will actually remove metals from the pool, the Iron Out and other Stain & Scale products ‘sequester’ the metals, or tie them up in a chemical straight-jacket, to keep them dissolved in solution. I would also suggest adding a Clarifier to the water, to help the filter trap suspended particles. Keep the chlorine level good with tablets, but avoid shocking for now if possible.

  17. […] more discussion on cloudy pool water, see Michael’s excellent post on the […]

  18. Faith Murray

    Okay, i read your article. For clarification, my pool is a simple above ground pool,14ft by 42in tall. Has about 3350 gal of water.

    My numbers acording to my simple test are normally,
    Total hardness: about 250
    Total chlorine: 3-7
    Free chlorine: 3-7
    PH: 7.8 before adding pH drop, 7.0 after
    Total alkalinity: about 120
    Stabilizer: about 80-100

    After some neighbors took a dip without letting us know, it got cloudy then green. We shocked it twice before it turned cloudy. It’s been 2 weeks and still cloudy. We keep adjusting pH daily, here in south texas it’s been 100+ the past week, pool chlorine is coming from chlorine tablets and shock. Longest without treatment was 2 days, still cloudy.

    We’ve added clearifier every other day to no avail.

    Vacuum? Yep. 24/7 pump and filter running? Yep. Changed filters? Yep. Good water dischage? Yep, and about that, when we fill a clear glass with discharged water its also cloudy! Have we drained the pool? About to if we can get it cleared.

    So, if everything is balanced, we can swim in it even though its cloudy? Or what are we missing thats keeping it cloudy?

    • Hi Faith, sounds like you have most of the bases covered, good circulation, sanitation and filtration. Too much clarifier however, can backfire, and actually become a dispersant, rather than a coagulant. Not sure if that has happened in your case, but possibly. I would also suspect that you have a small cartridge filter. You indicate that you have replaced the cartridge, which was a good move, at least annually I would think. Adding a 1/4 cup of aluminium sulfate, aka “Alum for pools”, to the skimmer, will help a small cartridge filter trap cloudy debris, but should be used only as a last resort, as it can gum up a cartridge filter if used too much, for too long the Slime Bag is a good way to increase the filtration ability of a small cartridge or sand filter. Connects to the wall return, and filters the water again.

      Can you swim in a cloudy pool? Sure if it has a good chlorine level and is being circulated. Pools can be sanitary without being clear – however it does add some risk, as you cannot see the bottom, which is why commercial pools would be shut down if the bottom is not clearly visible.

  19. Is it possible that 5 year old paint on my pool can cause cloudy water. Water chemistry is good and we have added flocculant and back washing, all to no avail. The paint is obviously fading and wearing off of the pool surface. It is a plaster surface that I think had been painted previous to our purchase, and we re-painted about 5 years ago.

    • Hi Jim, yes it can, especially in cases of low pH and alkalinity and calcium hardness levels. Rub your hand over the wall, if you get ‘chalking’, or residue on your hand that is the paint coming off. Keep filtering, a clarifier can help clear the pool faster…

  20. Steven Wright

    our pool guy told us that it is a common thing for our pool to get cloudy years after being resurfaced. we had done about 5 years ago, now the water is becoming cloudy and continuing to get cloudier. He, our pool guy, has recommended draining the pool and refilling it. any thoughts?

    • Davy Merino

      Hi Steven, cloudy pools are not uncommon, but nothing to do with the plaster, except in the first few months after plastering. It could be from very high levels of total dissolved solids, hence the suggestion to drain and refill. Fresh water every 5 years can make pool management easier, no doubt about it. Another key factor to water clarity is the effectiveness of the filter, and the number of hours running each day. Over time, filter media (sand or cartridges) wear out and need replacement, as they can no longer trap the really small particles. Finally, water balance (pH, alk, calcium hardness) is an important component, when water is not balanced, it can precipitate normally invisible minerals and make cloudy water. And chlorine levels too – if they drop too low, you will quickly see cloudy water. So, although draining and refilling will likely help, take a look at these other causes of cloudy water – filtration, circulation, sanitation and water balance – to fix the full problem.

      • Steven Wright

        thank you Davy. this guy just took over the business and has started using dry chlorine instead of liquid. our filter is only a couple of years old and is well maintained. Im thinking the switch to dry chlorine and the amount of time we were getting away with running the filter using the liquid may be the culprit. I am going to increase the time and see if it helps. we have never had a problem before and when I say cloudy, I can see the bottom very well, its just starting to get “that look”
        I’ll keep you posted. Thank you again for your quick reply.

        • Davy Merino

          Hi again – if by dry chlorine you mean granular chlorine, that could cause water cloudiness in two ways – first, it’s likely cal hypo, which contains calcium and if your pool has very high calcium levels already, it can take awhile for the calcium to dissolve, secondly using granular chlorine to sanitize a pool is not good because the level goes high very quickly, then tapers off rapidly, resulting in peaks and valleys of chlorination, and during a low valley, the water begins to turn hazy, until he shows up and zaps it again. Slow feeding chlorine tablets through a chlorinator, or using 5-gal liquid chlorine WITH a chlorine pump is the best way, to chlorinate consistently throughout the day.

  21. Hi, we just recently shocked, and treated with algaecide our vinyl pool and came back the next day to find large, white strips, or “wisps” floating in the pool. We have no idea what it is, and don’t know what our solution could be.

    • Hi Zoe, not sure either, could be ‘white mold’, or some sort of reaction occurs between shock and solids, or perhaps the algaecide, coupled with a high pH. Skim out the stuff, run the filter overtime, and apply a dose of clarifier to help. Keep chlorine level high and pH level low.

  22. Hi! We have a metal frame pool, holds 3500 gallon. We use a salt water system. We recently had to replace the pool pump itself. Now our pool is a cloudy green color. I’ve shocked it, added a clarifier, baking solda, algicide…you name it’s been put in the pool. Today I checked the levels and the chlorine level is at a 10, clearly can’t swim in this. I turned off the salt water pump and left the regular pump running. How can I get rid of the cloudy green color, I want my pretty clear blue pool back 😰😢 overly frustrated!

    • Hows the filter cartridge? Might need to be replaced – those tiny things only last about 3 months, and if they have to deal with heavy work, like algae, they can fail. Also, are you running the pump 24/7, to help clear the water faster? When it’s really hot (like now), those little pumps need to run longer, at least 12 hours per day, if not more. If the water is still green, you need more shock, even though it reads 10 ppm, if the water is still green… needs more shock. Add 1.5 gals of bleach, or 1.5 lbs of pool shock. Be sure pH level is 7.2-7.4 before shocking. If there is sediment or debris on the floor, vacuum before shocking if possible. Brush pool, filter 24/7, add clarifier the next day, use algaecide only when chlorine level drops to normal ranges, high levels will destroy algaecide.

      • It’s a brand new filter we put in when we replaced the pump! Should I use a chlorine free shock since my chlorine is so high? It’s starting to look milky green now 😰

        • OK, good that the filter is new – you may need another after this episode is passed – use chlorine, not non-chlor, 10 ppm is high, but you need to go to 30 ppm to kill the algae, and then you need lots of filtering and cleaning.

  23. A German chocolate cake with lots of coconut ended up in my pool. Pool is milky and oiled. Any suggestions?

    • Wow, that’s a good one. Enzymes are the ticket for oily gunk – Pool Perfect is the classic pool enzyme, by Natural Chemistry. Pool First Aid can also be used. Keep the insides of the skimmer scrubbed out clean, that will reduce scum line around the tile, and run the filter overtime. Check and balance all chemical levels, and elevate chlorine somewhat. You’ll get it back, and always have a funny story to tell.

  24. Craig Jefson

    Good Morning Mike,

    First, appreciate your Blog and the information you are providing pool owners.

    Second, I have a pool situation I would be interested in hearing your response to…gunite pool, chlorine tablets, running pump about 16 hours a day, automatic cleaner, cartridge filter cleaned (pool company cleaned and soaked filters), etc.

    Recently had my pool water tested. The CYA level was at 95 about 2/3 weeks ago. Used cyanuric acid reducer and tested the following week, level was a 90. Tested again yesterday and its down to 80 (progress?).

    It was also suggested I scrub the walls and pool floor. When I did this the pool became cloudy (milky). Pool company said this was probably “dead algae” (pool never turned green, actually always clear blue) and that I should shock it and allow the pool pump to filter the water.

    I did this about 4:00 pm yesterday and this morning the pool water is much less cloudy (more of a light haze).

    I would appreciate any feedback you can provide (e.g. on the right track?; anything I should do currently?; suggestions moving forward…shock weekly, scrub weekly, etc.

    Thanks for being available and for any feedback you can provide.

    Craig

    • Hi Craig, glad to see that the cyanuric acid reducer works a little bit, although it claims to reduce 50 ppm, per treatment (Bio-Active). If possible to replace some of the water, a foot or two, that is another way to reduce cya levels, and also reduces total dissolved solids.

      For the cloudy water – from brushing the pool, I guess the pool walls were just very dusty? Maybe a good vacuuming to waste could help. Or just start brushing it weekly, it’s good for the plaster, and good exercise for you too. Shocking weekly is not needed, unless you have visible algae, measureable chloramines, or allowed chlorine levels to drop to zero, or for pump problems, filter problems, or after a large party with numerous swimmers for many hours, or if the pool becomes contaminated with something yucky – other than that, if it looks fine, no need to shock, save your money.

  25. Victoria Hodgson

    Hi,I don’t know what’s going with my above ground pool,my water is so cloudy even I can’t see the bottom.I s been like that for over a week I shocked with almost 4lb and remains the same.please advice. I got my water tested and told everything is okey!!!

    • Davy Merino

      Hi Victoria, probably a filter issue. When the water is spot-on balanced, and the chlorine level is good and steady – look at the circulation and filtration. Could be time for a new filter cartridge or filter sand. Clarifiers can be used to help your filter trap small particles more effectively, but be careful not to overdose. Purifiber can be used as a filter aid for cartridge filters, just a cup added to the skimmer. Alum (Aluminum Sulfate) can be used as a flocculent for extreme cloudy water, very effective but you must be able to vacuum to waste, the following day. Not related to filtration, but for pools with high levels of dissolved solids (TDS), draining and refilling half of the pool can often be a big help, to remove half of the solids and suspended material, which can help the filter out tremendously.

  26. just bought a new sand filter when we started it up a it blow out a cloud of dust and days later our pool is very cloudy we tried balancing but nothing is working the pool has been on day in day out Help the kids want to swim

    • Hi Martha, sand filters often blow out a lot of ‘sand dust’ upon initial start-up, with new sand. Starting the filter on the Rinse setting will avoid this. Unrelated to your cloudy water issue – unless one of the laterals in the tank bottom is releasing sand – if you find sand in the pool, constantly, not just a handful after start-up, the laterals or standpipe in the filter could be allowing water to bypass (not filtering the water). Also could be caused If the wrong type of sand was used (should be #20 silica sand, .45-.55 mm graded, labeled “Pool Filter Sand”). Other issues could be plumbing the filter valve incorrectly. the PUMP port should connect to the pump pipe and the RETURN port should connect to the return line. Third issue with cloudy water, since you are running the pump 24/7, should be poor water balance or low chlorine levels, or possibly high levels of phosphates contaminating the water. Assuming that the filter is not undersized, you can use some clarifier to help the filter trap small debris (with good water balance and chlorine levels too).

  27. Mike,
    I overdid my 14 foot above-ground pool on soda ash to raise the pH and overall alkalinity, and now I can’t see anything beyond the top. I treated it about 11 hours ago and no change. Any suggestions to clear it up, and is it safe to swim in? My numbers on the strip test are good except calcium is low, but I don’t plan to mess anymore with that until I can figure out what to do about the murkiness.
    Thanks! Wade

    • Hi Wade, carbonates and bicarbonates often make good water clouding materials. If your pH and/or alkalinity is now too high – lowering it with acid may reabsorb the carbonates into solution. I would adjust the calcium hardness too, if very low (under 150 ppm), that could be contributing to the problem. Clarifiers can also be used, to help trap the material in the filter for backwashing.

  28. Pool was clear when we opened and has stayed clear until just yesterday. the chlorine levels were high and ph was a little low so we dialed down the level of chlorine. opened pool yesterday and it was cloudy and no chlorine is registering. We turned up the level of chlorine and shocked the pool. How long will it be before we should see a chlorine reading. We are thinking of adding liquid chlorine today. Any help would be great.

    • Hi Cheryl, you should see a chlorine reading immediately after adding shock chlorine. Well, maybe a few minutes for it to disperse, but right away. If you add chlorine, possibly a lot of chlorine, and see no reading on your test… 1) bad test strip or reagent, 2) chlorine demand is higher than supply (something is consuming it) 3) no stabilzer in the pool, add 4 lbs of cyanuric acid per 10K gals 4) too much stabilizer in pool, keep it 20-50 ppm, or 5) pool water needs more filtering each day, or filter media is old/dirty, or filter/valve problems are allowing water to bypass filter media. Very often, it is a combination of more than one of these. Hope this helps (saw your other post too) – Davy

  29. My pool is very cloudy I guess that milky or blur gray. It started very green I have green cleared
    I have Brushed, vacuum been in it put tons of shock, chlorine raised all levels up not sure his go get acid up it is testing low on that
    Had water tested they tell me phosphate levels are high (3417) I’ve done flocculant which did nothing
    Water isn’t clear I can’t see what’s on bottom and really don’t want to get back in until I can see bottom. Any suggestions ? I just shocked About 4-5 days ago did 5 bags of shock have 30k water
    I have shocked pool numberous times last month not had clear water since I took top off
    Any help would be appreciated

    • Hi Tina, 3417 phosphate level is 11x the suggested minimum level of 300 ppb. I would treat the pool with The PhosFree Extra Strength, following label instructions carefully. If you can’t drain the pool and refill it, which is also a valid suggestion. There is some sort of extreme contamination going on, perhaps nearby mulch beds or planters are overflowing into the pool. Perhaps fertilizer found it’s way into the pool from backyard landscaping efforts. Perhaps the fill water for the pool (from the hose) is contaminated. This should be addressed or you will have continued problems with algae and cloudy water. After treatment of Phosphate remover, retest the levels, you can buy your own $10 phosphate test kit. The pool may need several treatments to remove such a high level of phosphates, so if you can drain or partially drain and refill, that would get you swimming much sooner, and give you less problems down the road. Especially if the pool water has not been changed in over 5 years, it likely is choked with many other solids, beside phosphates and nitrates, which is contributing to the cloudy water conditions. But if draining is not possible, bring the phosphates down below 300 ppb, and then shock the pool – hard – 9-12 lbs would not be unusual in a pool your size. And… try to solve the phosphate mystery, what has contaminated the pool? It could happen again if you don’t find out!

  30. Accidentally put 2 bags of shock (some website said the pool had 20,000 gals, in reality it’s actually 8,000 gals. Each bag was 10k worth. Should I dump all the water and restart?

    • Hi, no need to drain. It will come down on it’s own over time. A few days usually. No problem.

  31. Doretta Braden

    Our pool was green when we opened it. Added lots of chlorine and got the green out but now it’s so cloudy we can’t see the bottom. We backwashed several times trying to clear up the green and now realize we forgot to rinse. I suspect the cloudiness is due to that. I’ve used a clarifier with minimal results. Should we brush the sides & bottom or try vacuum to waste or try a floculant?

    • Hi, Rinsing doesn’t do much – probably not the cause, there is just a lot of material that is overwhelming the filter. If there is a noticeable sediment layer on the floor, vacuuming to waste is a good idea. If not much, then brushing would be preferred. Other tips to clear the water – run the filter 24/7, balance the water chemistry (ph, alk, calcium, cyanuric), and resist the urge to backwash the filter, until the pressure gauge is 5-7 lbs above the clean pressure, or until water flow is noticeably diminished. You can retreat with a clarifer after 5-7 days of a previous treatment. If no better after a week, you may consider replacing the filter sand.

  32. The salt cholorinator stopped working. Cloudy Algae looking water. Water took down turn. Shocked then chorine nothing changed. Raised my alkalinity from 40 to 90 ppm with soda a. Raised ph to low end. Plenty chorine available. Still shows it needs soda ash some. Add more soda ash or give it a day or two. 26,000 ga pool approx

    • Davy Merino

      If you are still trying to kill, algae – the chlorine is much more effective at a 7.0 – 7.2 range. So, I’d probably keep it low until the water starts to clear. If the pool is still green, shock again, but keep adding it until the water turns a blue/grey color, and stays that way. If it still has a tinge of green, or if the chlorine level drops to zero after 8 hours, you need to add more shock, to make a complete kill or oxidation of the algae.

  33. Got one for you Mike…We had to drain most of pool this spring and do a lite repair, due to the cost of a refile or we had to use well water we decide to pump water out of the creek. The creek looks like ice tea ie: tannin colored, what if anything can be done to clear this water. I do have to add when you scoop out a class of water it looks clear…Thanks in advance Curtis

    • Davy Merino

      Hi, I’ve had a friend of mine fill his pool from the creek. I thought he was nuts, but it turned out OK. It was a little murky and tan colored at first, but he tested and balanced the pool water, and circulated a metal out product (sequestering agent) and some clarifier overnight, and then shocked the pool to a blue color the next day – no problems!

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