Bad Pool Chemical Combinations

bad pool chemical combinations

There are a handful of water balance scenarios that can result in unfortunate side effects. In addition, there are some pool chemicals that should never be mixed or added to the pool at the same time. Once we’ve addressed those scenarios, we’ll close with a brief discussion on best chemical safety practices to prevent accidents.

Let’s dive in, shall we?

Bad Water Balance Combinations

poor pool water balance

As you’re probably already aware, unbalanced pool water can cause a lot of problems. Bad water balance can cause poor water clarity, inefficient sanitation, stains and scale buildup, and let’s not forget corrosion of pool equipment and accessories. If you’re not familiar with proper water balance practices, visit our blog post, “The Ultimate Guide to Pool Water Balance.”

High pH + High Calcium Hardness

This is a recipe for scaling and cloudy water. Can form scale film on pool surfaces and pipes, and can may even form sharp crystallized nodules of calcium that can snag swimsuits and scratch skin.

High pH + Low Chlorine

Perfect conditions for cloudy water and algae. Algae prefers a high pH level, and is just waiting for a low chlorine opportunity to bloom.

Low pH + Low Total Alkalinity

Will cause etching and corrosion to steel, copper, rubber, vinyl, and plaster surfaces. Acidic water wastes no time in corroding pool surfaces and equipment.

Low pH + High Total Alkalinity

Same as above, only it becomes harder to raise pH, due to the buffering effect of a high Total Alkalinity. You can find more in our blog about the relationship between pool pH and Total Alkalinity and how to fix balance issues.

Low Chlorine + Low Stabilizer

Low stabilizer can cause chlorine to be more quickly destroyed by the sun, which can compound the problem of low sanitizer levels. Hazy, to cloudy, to green is the usual progression of water in this condition. If you look at your pool carefully every day, you’ll know just by looking at it when chlorine is low.

High Chlorine + High Stabilizer

This can damage soft and shiny surfaces over years of very high chlorine levels (5-10 ppm). Stabilizer (Cyanuric Acid) levels over 100 ppm can cause problems in chlorine potency, and chlorine testing becomes unreliable.

High Combined Chlorine

Chloramines are chlorine molecules that have joined with ammonia or nitrogen. No longer an active sanitizer, they cause red eyes and smelly pools. You can find chloramine levels by subtracting Free Available Chlorine from your Total Available Chlorine reading (TAC-FAC=CC). When chloramine levels exceed 0.3 ppm, shock the pool.

Low Calcium Hardness

Creates a corrosive water condition, which causes etching and leaching of calcium from plaster or tile grout. Low Calcium Hardness is also bad for vinyl liners when the water is too soft. It can hinder overall water balance and chemical effectiveness, too.

High Phosphates

Phosphates enter the pool from many sources, and are a favorite food source for algae. When a phosphate test exceeds 300 ppb (parts per billion), address levels with a phosphate remover.

Bad Pool Chemical Combinations

avoid bad pool chemical combinations

While balancing and maintaining your pool, you have to be very careful and deliberate with pool chemical applications. If chemicals are added in the wrong order, at the same time, or without enough time between applications, your pool can suffer. ALWAYS read and follow product label instructions to ensure the best results and prevent accidents.

Raw Chemical Interactions

Never allow pool chemicals to contact each other. Go back and read that sentence again. Harmful reactions may happen, even outside of the pool. Chlorine mixed with any other chemical or foreign substance can emit toxic gases, erupt in flames, explode, or all of the above. Always store chemicals in properly sealed containers in an area that’s cool, dry, well ventilated, and secure.

Chlorine Shock + Algaecide

Chlorine shock will disrupt the polymer chains and chemical compounds used in many pool algaecides. In most cases, pool shock will completely destroy the algaecide. When necessary, use pool shock to kill algae, then wait to add algaecide until after the chlorine level has returned to normal. When adding algaecide, be careful not to overdose it, or you may end up with surface stains and foamy water, depending on which type of algaecide you use.

Chlorine Shock + Enzymes

Again, chlorine shock will break down any enzymes you put into the pool. If you’re going to use enzymes, add them after chlorine levels return to normal. Otherwise, you’re just wasting your money.

Chlorine Shock + Sequestering Agent

Chlorine shock will also disrupt stain and scale chemicals, a.k.a. chelators or sequestering agents, if they’re added at the same time. Add stain and scale chemicals either a day before or several days after you shock the pool.

Chlorine Shock + High Metals

Metals in the pool can come from a few different things, the most common being your water source or poor water balance eroding the metals in your pool. When you have high metal levels, shocking the pool can drop them out of solution and cause pool stains. Keep pH, Total Alkalinity, and Calcium Hardness within range, and add a regular treatment of a sequestering agent like Stain Away or Metal Free to keep metals in solution.

Chlorine Shock + Trichlor Tablets

NEVER pour cal-hypo or dichlor pool shock into the pool through the skimmer. This is especially true if you have an inline automatic chlorine feeder filled with stabilized chlorine tablets. The resulting reaction between trichlor tablets and your pool shock can cause a chemical fire or explosion that will destroy your pool equipment and/or cause serious injury. Always follow product label directions when adding shock to your pool, and be sure to broadcast it evenly instead of concentrating your application in one spot.

Chlorine + Muriatic Acid

When mixed, these two chemicals create a dangerous toxic gas that can be harmful or even deadly if inhaled. Carefully read and follow product label directions to prevent an adverse reaction. Never add muriatic acid to the pool when chlorine levels are high, and don’t shock the pool immediately after adding muriatic acid to the water.

Cyanuric Acid + Stabilized Chlorine

The only reason you should need to use stabilizer or conditioner, otherwise known as Cyanuric Acid (CYA), in your pool is if it’s a fresh fill, if there’s been a lot of splash-out that brought the levels too low, or if you’re using an unstabilized form of chlorine as your primary sanitizer (such as with a salt water chlorine generator). Stabilized chlorine, like the 3″ trichlor tablets in your chlorine feeder, contain a small amount of CYA in each tablet. If you’re doubling up on CYA, you’ll soon find that the levels are too high, and you’ll have an even bigger problem to deal with to bring those levels back in range. Spoiler alert: it involves partially draining and refilling your pool to dilute it.

Calcium Hardness Increaser + pH/Alkalinity Increaser

Adding a Hardness Increaser too close together with sodium carbonate (pH Increaser) or sodium bicarbonate (Alkalinity Increaser) can cause an adverse reaction. The result is often cloudy water, but it can also cause small solids to appear in the water. In addition, this reaction can accelerate scale buildup in the pool.

Clarifier + Clarifier

If you overdose a pool with clarifier, a curious phenomenon can occur. Instead of behaving as a coagulant, the electron charge can reverse, causing some formulas to behave as a dispersant. Wait 5-7 days if you have to treat the water with clarifier again, and again, always follow dosing and application instructions found on the product label.

Best Practice Pool Chemical Tips

pool chemicals and water testing

When it comes to pool chemical application, a few quick tips will help you avoid most of the scenarios listed above. These general chemical handling and safety guidelines will not only keep you safe, but they’ll help to keep your pool safe and damage-free, as well.

Run the Pump

In most cases, pool chemicals should only be added to the pool when the pump is running. That said, there are a few exceptions to this rule. We’ve said it before, and we’ll say it again, always, always, ALWAYS carefully read and follow the directions on the product label before applying any chemicals to the pool.

Wear PPE (Personal Protective Equipment)

When handling chemicals, it’s important to wear personal protective equipment, including safety glasses and chemical gloves. Avoid inhaling fumes, and wear a respirator if necessary. Familiarize yourself with the safety data sheet (SDS) in case of accidental skin or eye contact, inhalation, or ingestion.

Prevent Negative Chemical Reactions – Read the Label!

Never add chemicals at the same time, whether you’re balancing the water, shocking the pool, or adding a specialty chemical. For most water balance changes, the pump needs to run on the high setting for at least four hours before you can add another chemical or retest the water. The product label will provide more accurate instructions on wait times before adding more chemicals or going swimming.

If the chemical you’re using requires dilution, always add chemicals to water. NEVER add water to the chemicals, or you’ll risk initiating a dangerous chemical reaction. Start with a clean bucket of water, and dissolve the chemicals in the water before adding it to the pool.

Don’t add anything to the water when chlorine levels are high. Some chemicals will be rendered useless, and others can start an adverse chain reaction. It’s best to wait until chlorine levels return to normal before treating your pool any further.

Storage is Key

As we mentioned earlier, storing your chemicals properly is an important part of chemical safety. Containers should be properly sealed and stored separately in a cool, dry, clean, and well-ventilated area that can be easily secured. Children and pets should not be able to access your pool chemicals.

Conclusion

When used properly according to product label directions, pool chemicals are an important part of maintaining a healthy swimming pool. If you have questions about pool chemicals and specific water balance issues, check out our blog full of water chemistry and pool care tips!

Until next time, class is adjourned. Happy swimming!

176 thoughts on “Bad Pool Chemical Combinations

  1. Patricia Rivera

    Hi, I am in the process of closing my pool for the winter. Hoping to get the cover on today. It is an inground pool, vinyl liner. I added chemicals 2 hours ago to raise the alkalinity it’s almost there. It says to test again after 4 hours. My question is can I add winter algicide now ( it says add algicide and run filter fir 2 hrs then you can close pool) or should I wait another 2 hrs to add that if levels are good?

    • Hi, you can add the algaecide now. I usually like to wait until I’ve lowered the water level, so as not to waste chemical, or pump it out across the lawn. I believe that it will disperse quite thoroughly, without running the filter.

  2. Coral Harper

    Hi we just inherited a pool with a deep green algae. I reduced the ph and shocked with chlorine (which is now high) but ph is back up to 7.4. Should I re reduce ph?, add flocculant? abandon all hope?
    It’s been green for 2 weeks as my futile attempts at learning the ropes have failed. Help please!!!

    • Hi Coral, pH of 7.4 is not high, did you mean 8.4? Algae gives off base, and will raise the pH. If the pool is still green, it needs more shock, and may need a lot of it. keep adding until it turns blue/grey. If it has been green for the whole summer, it may be better to drain the pool, clean and refill, or drain half and refill. Your filter may not be effective enough to filter out all of the solids, and could be hindering the process. Is the pool clean? If it has leaves and debris, that will thwart your attempts to clear the algae. If you can vacuum to waste (with a multiport valve), you can floc with Aluminum Sulfate, (aka Alum), using 4 lbs per 10K gals, and 4 lbs of shock per 10K gals, shut off the pump and let it settle overnight, then vacuum very slowly to waste.

      • Coral Harper

        Thank you. 🙏 so helpful. Only been green for 2 weeks. Still green after 2.5k granula shock (12mx3.5mx1.5m depth) Pool was clean, but can’t see the bottom now. Have brush vacuumed every day to waste. Can I floc at the same time as chlorine or after? Sorry~ complete novice

        • Floc can be added about an hour after the shocking, and brushing. Floc in a bottle won’t do much usually, look for granular-flake Aluminum Sulfate (Alum). Fill the pool full before vacuuming, because you need to go very slow, to not disturb the fall-out too much (it’s like wet toilet paper!)

  3. Roger Burton II

    I have a hot tub heated pool combination. the PH is real low. But every time I add PH up or baking soda it turns blue and bubbles real bad. Do you have any idea why this would happen ??

    • Most likely a high level of copper in the water. It may begin to stain the pool if it has not already. Use a chemical like Stain Away, to keep the metals in solution.

  4. I added 20 oz of Phosfree to my 14,000 gallon above ground pool and 45 minutes later added (2) packets of granular chlorine. The bottom of my pool had 3-4 dark splotches that eventually went away after about 2 hours. Not sure if the 2 chemicals were working against each other but it was concerning for those couple hours because I was closing down the pool for the winter.

  5. Andre Kelley

    Doc,
    We had several days of rain in our area. In that time, my 12x26x4 above-ground pool turned a beautiful shade of green! Shocked it, scrubbed and vacuumed and ran the filter non-stop. Got it back to blue, but murky now. pH was low so added pH-Up. Still murky. Added recommended dose of algaecide, still murky. Filter runs all the time and i change cartridges every12 hours. Help!

    • Hello, I would try a Clarifier next, with recommended dosage. If that does not help, perhaps a new set of cartridges would do it.

  6. I have a 12’x36” Intex pool. I added 8 tsp chlorine granules this morning, pool is clear, but I added 1 cup of algaecide at the same time. Didn’t know to wait for chlorine to drop first. Is the water safe to use, or will bad chemicals from reaction remain?

    Chlorine reading is now 3.0, filter pump has been running for 8 hours.

    • Mike, the pool is safe to use – there’s no dangerous reaction from adding the two, only that high levels of chlorine will destroy the algaecide, or waste it.

  7. Hi – how long should you wait between Shocking and Adding a Clarifier?

    • I would wait at least 24 hours, before adding Clarifier, and wait another 5 days before re-dosing.

      • Rick Nunez

        I have high phosphate and algae I just shocked the pool this morning @11am how long should I wait to add phosphate remover?

        • Hi Rick, not sure if it matters, but for ‘testing’ for phosphates, the instructions say that chlorine should be below 5 ppm. For using phosphate remover however, it may not matter. Consult the label, and if not mentioned, go for it and add it in…

  8. ALFRED GANGEMI

    I think input this in the wrong page, so I’ll repost:

    After the recent tropical storm, I lost power for a week. When power restored, I refilled pool from what evaporated and shocked with 1 gal liquid. Over the next couple of days I could not get my chlorine levels to rise, so I shocked again with another 1 gal liquid. All chemical readings were good besides chlorine, but now all seem out of whack. Any suggestions?

    FCL .05
    TCL .34
    CCL .29
    pH 7.1
    Alk 68
    CH 154
    CYA 91

    New: I did just add about 18-20oz of 30% non-foaming algaecide to tackle what the group of leaves left on certain sections of the bottom of pool.

    • Hi Alfred, you do need a good shock, to get rid of the combined. The high CYA may be part of the problem, but also 1 gallon may not be enough to overcome the CYA and whatever else may be in the water, consuming the chlorine. I don’t recall your pool size, but I would shock with 1 gal per 5000 gals of pool water and see how that does to the TCL and to the FCL.

      • ALFRED GANGEMI

        Thanks! I have a kidney bean pool, and my guess it is around 15k gallons definitely not more than 20k. I only have 1 gallon shock on hand, so I’ll have to get more. Is it possible to overstock the pool? Doing more harm then good? I think at 1 gallon at 5k, then I’ll get a case of four and use all of it.

        Now that I need new algaecide, which In The Swim do you recommend 60 plus or the copper one? I’m on Long Island, NY and our water is pumped from 25 wells, some approaching 700 feet deep.

        • I like both algaecides, both very powerful. Overuse of copper algaecide can lead to staining however.

  9. Angela Holt

    Hello, I have 24′ round pool 52″ deep (13000 gallons roughly). I recently uncovered my pool and found algae growth and greenish cloudy water.
    I’ve shocked it yesterday evening, and I’m not getting a chlorine reading at all…🤷‍♀️ My PH is the lowest on my reader (an orangish red color). I’m afraid to keep adding chemicals in fear of locking up the chemicals. HELP! LOL So far today I’ve added PH increaser aprox 2lbs (no results), and I added a half cup of devolved copper sulfate.
    Should I shock again tomorrow? Or do I need to just start over with my water?🤦‍♀️

    • Yes shock again, using 3 lbs of shock, you may have high levels of ammonia or nitrates, preventing a chlorine reading.

  10. Hi I shocked my pool first and forgot to ph down first and ph is high! Can I ph down still? If yes how long after thanks

    • Yes, go ahead and drop the pH now. It may have wasted some of the shock added before, but no worries, I’ll bet you will always remember from now on! No need to wait, you can add pH down and chlorine within a few minutes of each other.

  11. Tiffany McArthur

    I have an 18’ above ground pool.. here are my chemical stats:
    Total hardness. 110
    Total chlorine. 1
    Free chlorine. 0
    Ph. 8.4
    Total alkalinity. 180
    Stabilize. 100

    My pool is green/cloudy/slimy!
    Please help me determine what, and how much, chemicals I need and what order to add them to pool

    • For a 7500 gal pool, Lower the pH level to 7.2, using 46 oz of muriatic acid or 2 lbs of dry acid (pH Decreaser), and then shock the pool to about 20 ppm, with 2 lbs of granular shock (Cal Hypo). Run the filter non-stop, 24/7. Actually, noting your alkalinity and stabilizer levels, it would be best to drain half the pool and refill after treating with the chemicals. Since you may not have a main drain, consider renting a submersible pump to drain the pool rapidly, so you can refill again quickly, to resume filtering.

  12. Delta Gatewood

    Pool is crystal clear, but reading no chlorine! And a high ph. We have these algae stains forming in the deep end, and it seems like they can be removed with lots of force with a metal brush and chlorine..it breaks up in little black pieces; at least that’s the color we see from the surface. I looked at it closely under water and it looked green? I’m assuming it’s these stains that are causing the high ph and zero chlorine?! Tested water today, free chlorine and stabilizer at 0! Ph 8.0, alkalinity 110, calcium hardness 200 and total dissolved solids 2,000. We have a 11,948 gallon marcite/gunite pool. Any idea how to stabilize it all and remove the stains? To me, I think it needs alotttt of chlorine and scrubbing, but don’t want to mess anything up.

    • Delta, add two (2) lbs of pH Decreaser (Sodium Bisulfate), and then add 3 lbs of granular pool shock (Cal Hypo). Then add 3 lbs of Stabilizer (Cyanuric Acid) to help protect the chlorine from depletion by the sun. The algae could be blue/green algae, Black algae can have a slight green hue, but is mostly black in color. Also I would recommend that you begin using a good quality algaecide, with “60” in the name, commonly called Poly 60, or what we call Algaecide 60 Plus. After the heavy shock of 3 lbs – test the water after 24 hours, if you still do not have a chlorine reading, shock again, this time with 4 lbs of Cal Hypo, and also get a different test kit or strip, to be certain that they are working properly, and not giving you false readings. Keep the chlorine above 3 ppm, and the pH below 7.4, and use weekly algaecide. Scrub off the algae as much as possible, and vacuum the heads to waste, or backwash after vacuuming. Once under control, (the algae), change the filter media (sand or cartridge or grids) which can harbor the algae spores, making regeneration easier and more likely.

  13. Matt McNaught

    Hello,

    All levels were perfect, except hardness was way too low. Added 50lb calcium chloride (solid) over three increments per the instructions. By the next morning, TC and FC were zero, added two gallons shock and cranked tab feeder all the way up. TC and FC are still zero. Tried test strips from two different bottles. Other readings are still normal and hardness is perfect.
    ~30,000gal in ground vinyl liner pool

    No way chlorine is really zero. Water was and still is crystal clear four days later.

    • Hi Matt, it could be that the liquid had lost its potency, which can happen in under 1 year. Or, you may have invisible consumers of chlorine in the pool, not uncommon, usually nitrates or ammonia. When folks have trouble getting a chlorine level, my first advice is usually a triple-shock, or 3 lbs per 10,000 gals, to destroy such invisible stuff eating all the chlorine. If you have a sunny pool, you also will want to have a little cyanuric acid level of 20 ppm minimum (aka stabilizer).

  14. I came home from a weeks vacation around 6pm, my strip read low ph and alkaline. Chlorine read normal. I added alkaline and ph increase at the same time. Within an hour my water turned cloudy. 7am the next morning it was still cloudy so we back filled the filter and threw the robot vac in. its now 2pm and no change. any suggestions? Everytime I use a test strip it says everything is fine but chlorine is high. I didnt add chlorine?

    • Low chlorine is a main cause of cloudy water. If you’ve not added any, for over a week (?), that does not sound right. I would shock the pool, to raise chlorine level above 10 ppm, and recheck chlorine again, might have bad test strips perhaps. Clarifier can be used, to help enlarge the suspended particles for filtering.

  15. Lisa Foster

    My water has been clear all summer. After July 4th my pool was full of firework debris which we got out but ever since has been just a little hazy but water tests perfect for chlorine ph and alkalinity. Went to have water professionally tested they said add 6 lbs shock, phosphate remover (32 oz), clarifier (4 oz) and algaecide 2000 (6 oz). I did this all at once and now my water is just one big cloud. Can’t see the bottom. 11,000 gal above ground vinyl liner

    • Wow – that’s a lot of shock for such a small pool. Phosphate remover will make the pool cloudy, but has very specific instructions on the correct use. Run the filter non-stop, and clean only when the psi rises about 5 lbs or more. You can add more Clarifier, but only every 5-7 days, and be careful not to overdose. Algaecide should not be added along with shock, as the shock will destroy it, render it useless. If it does not clear in a week, you can get some Aluminum Sulfate at the pool store, and add 4 lbs to the pool, then shut off the pump, and let it settle overnight. The next day, fill the pool high, and vacuum to waste, to remove the settled material (you must have a multiport, or some way to be able to vacuum to waste, to use Alum).

  16. My pool ph is 7.2-7.4 my chlorine level is between 2-4.
    It had been low on chlorine. And went about 2 weeks without shocking
    Well, we shocked it, vaccummed it,and the pump has been running 12 hours a day. Except its been running 24 hours now chlorine and ph is where it should be but its still super hazy and green.
    Should we use floc or clarifier? I feel like its probably microscopic pueces not being gotten.

    • Start with Clarifier, be careful not to overdose with it. Wait to clean filter until pressure rises. Keep the chlorine high and the pH low. If not getting better, you can floc it, but not with the stuff in the bottle, get granular Aluminum Sulfate (I think Leslies sells it), and add 3-4 lbs per 10K gallons, shut off the pump, and then vac to waste the following day.

  17. I put “IRON OUT” in my Intex pool (6,400 gallon) …all 5 pounds of it. My ugly brown pool with perfect readings was crystal clear with no chlorine and super low ph. I then saw you should not put “IRON OUT” in a pool. OH NO! I can’t drain and refill. I waited a day still no chlorine and ph low. I shocked it with half a 1lb package of shock and put my floater back in. Next day chlorine reads good ph still low. I added some ph up and am waiting on that reading. Will the “IRON OUT” dissipate from the water so that we can swim. I have been fighting this pool for 4 weeks and only got two swims out of the 4 weeks on two days it was green and somewhat tolerable to look at. It is beautiful looking now but I am worried the “IRON OUT” made it not safe to swim in……even if I get my readings correct…..please help me….

    • Found this online “Iron Out is not recommended for pool water. Iron Out is safe to use in an empty pool to remove staining from walls, liner, etc. just not in a full pool”. I think maybe you should drain the pool? Not sure though, perhaps you should call the company and ask them Summit Brands, 1.888.476.6688

      • Eileen Naturale

        Thank you for the information and number. I actually did email them and they did reply that the pools should probably be drained or at least half drained. I just wasn’t sure if maybe they couldn’t say it ok because of infringement purposes with other pool treatments since it is so much less expensive. Thank you for your input and it will probably and sadly be put away after it is drained. So bummed.

        • Eileen, why do you need to close the pool? Is water that expensive for you? In my area (Fairfax county, Va), we pay under $4 per 1000 gallons, and, if you tell the water authority that you are filling a pool, and provide meter readings, they often will not charge the sewer portion of the bill.

          • Eileen Naturale

            We have well water and we were taking a chance filling it first time and then it didn’t work out. To have a truck delivery is over $500. Just can’t afford it. So this season will be a bust. I was hoping to save the water but if I can’t, I can’t. Is there anyway to test for toxins? My kids will be disappointed but it’s been 4 weeks already. We have a community pool but it is not open this year. My husband was able to find a pool and not pay over retail which was rare. He actually got a good deal other wise we would not have been able to afford it. Just a bummer. I had no idea it would have gotten so complicated. 3 pool stores all different advice and nothing g worked until the iron out. I just made a too quick stupid move. I should have researched it more. It wasn’t until after it happened so fast that I thought how long until I can swim and dove (no pun intended) a little deeper and realized I probably made a mistake. 🙁

          • OH I see… 🙁 bummer. Perhaps half drain the pool, and maybe add 1000 gallons per day from the well? Or 500 gals, if you think it can handle it. Maybe try another call to the company, there may be a reducer, a chemical that will cancel out, or remove those put in the water, or some greater assurance that it won’t be harmful? Good luck!

  18. Dawn A Davis

    Hi, our chlorine is at the 1 to 2 rpm and PH is 7.2 and it has been that level a few days steady but the last 2 days it has turned cloudy green. Shocking would increase the chlorine more correct? Since it’s at a good level now. I added clearifier the regular one low dose last night with no change and today algaecide. Is that what I should have done? or do I need to shock it? or drain some and add some fresh water back? It has been perfect t all summer until we hit the 90s this week.

    • Dawn, you may be losing chlorine level during the hottest part of the day, and then algae grows. Shocking is the best method to kill algae, algaecide does not do it so well, despite the name. And shocking for algae would be a double or triple dose, look on the package, and do the math for your pool size, and then double or triple the amount, or keep adding until you see no more green, only blue/grey color. Then filter 24/7. Add clarifier every 5-7 days as needed. Then, when restored, use a weekly algaecide dose, and also increase the daily filtration time, what works well at 75 degrees is not enough at 90 degrees.

  19. Desiree Brower

    My alkalinity is super low, can I add large amounts of alkalinity increaser at a time?

  20. How long after adding sodium bisulfate, to lower ph from 7.6 to 7.5 or 7.4, should I wait before shocking the pool?

  21. Michael Beek

    I added 2 bags of shock to the pool and then a little Ultra-Bright Clarifier. Pool was clear all summer and every now-n-then, I add a little clarifier just to ensure pool stays crystal clear.

    I am think I am shouldn’t have added one right after the other? The pool turned a light green. Pool testing of water showed chemicals in balance and just needed a little alkalinity powder. Did I do a stupid thing by added the chemicals back-to-back?

    Phoenix, Arizona

    • Hi Michael, the Clarifier was likely destroyed by the shock chlorine, and the shock may have also dropped some copper out of solution, turning the pool a lime green color. No big issue, I’d expect it to filter out in a day or two, but if not, use a sequestering agent like Stain Away, Metal Free, Jack’s Magic Blue Stuff, to lock the metals back into solution, and then use a maintenance dose, per bottle label, to maintain it, as these chemicals degrade with sunlight and chlorine.

  22. How long do I wait after shocking my pool, before I add chlorine tablets?

    • No need to wait, you can add them right away, and it is best to have them there, already dissolving, than to wait until chlorine level drops close to zero, at which point the tablets may not dissolve fast enough to keep the chlorine level a minimum 1.0 ppm. Be sure you also have a good pH level, 7.2-7.4, where chlorine is most potent. At pH of 8.2, nearly half the chlorine is wasted.

  23. Hadley Bowen

    The pool was cloudy so I added too much clarafier. It was green the next morning. I vacuumed and added chlorine because I thought it was alge. Couple days later its still green and have a very strong chemical odor and eye/skin irritation. I then drained it 2/3 of the way and filled it with fresh water. Gave it 24 hours to filter through and no change. I have vacuumed and they is nothing on the bottom or in the pool water. I change the filter cartridge everyday. The cartridge is green but sitting in the sun the green with evaporate. I have since shocked it and still no change. What can I do?

    • Hadley, green is either going to be algae or copper ions. Copper will be clear green, algae is usually cloudy green. Copper is usually brilliant lime green, and algae is usually muted kelly green. If you think algae, keep adding shock until there is no green left. Could be 3-4 lbs per 10,000 gallons, or less. If you think copper, add a sequestering agent like our Stain Away chemical, to lock the metal in solution.

  24. My boyfriend put metal free to get rid of the high metals in the pool the next night I shocked the pool the pool turned a dark green color what do I do now ?

    • Ivona, the shock treatment can break apart the bonds that hold the metals dissolved in solution. Add another Initial Dose of the Metal Free or other sequestering agent, to put the metals (copper?) back into solution.

  25. Vinyl above ground pool: water is cloudy, hardness, total and free chlorine, ph, alkalinity, & stabilizer are all very low.
    Shocked the pool and added stabilizer, running pump 24/7. Water is still cloudy. Hardness, total and free chlorine, & stabilizer are still reading very low.
    Any advice on what to do?

    • Hi Nikki, high chlorine and low pH – focus on that, don’t worry about the hardness and alkalinity, just be sure the chlorine does not drop below 3 ppm. Check it every day, twice daily if needed, keep the chlorine level high. Then focus on the filtration, it is good that you are running 24/7. I suspect this is a small softsided pool, with a tiny filter? If so, it will take some time to clear, and will really struggle. Use a Clarifier weekly, per label instructions, to help the little guy. For faster clean-up, buy the Slime Bag and attach to your wall return as a secondary filter. Buy a second filter cartridge (Intex recommends new every 30 days) and after cleaning one, let it dry completely.

  26. Our alkalinity and copper levels are high. Chlorine level is low. The lady at the pool store recommended adding muriatic acid first, waiting four hours, then adding a sequestering agent. If I add the sequestering agent at 7pm on a Friday, when will it be safe to shock the pool? Would early Sunday morning be too soon?

    • That sounds about right, SUnday morning… it’s good to give the sequestering agent some time to work, as shock can deplete the chemical.

  27. My pool has alot things that aren’t balanced how long do I have to wait between adding chemicals?

  28. Currently battling high alkalinity its about 180ppm at the moment. Using sodium insulate to bring it down. 8500 gallon vinyl pool. How much should we be adding at once?

  29. Pool is cloudy-ph and alkalinity keep going from good to low, then the pool got cloudy, no chlorine reading although the hopper is full-pool is in full sun-noticed a lot of particulates in the pool, thought it was D.E. but we took the filter apart , washed it, put it back together and weighed out the DE according to the manufacturers specs on the filter-we haven’t been in the pool as much as usual, bought clarifier today-can I now adjust the alkalinity first, the work on the ph? please advise

    • Hi Sharon, more important than low pH and alkalinity is the low chlorine, which is why the pool is cloudy. Keep the chlorine high and the pH low, and run the filter longer than you think you need to, and your cloudy water problems will disappear! 🙂 PS – remember that 1 lb of DE powder measures 32 oz dry measure, not 16 oz, as one may think.

  30. Thank you for the article! Pool water was crystal clear, but the alkalinity was low (46) so we added sodium bicarbonate. Also added chlorine shock at the same time because the chlorine was low (1.5) and the pool hadn’t been shocked in a couple of weeks. And added lanthanum chloride (Perfect Weekly from Leslie’s Pool store) at the same time. Pool immediately turned very cloudy and is still cloudy hours later. Any ideas?

    • It could be a reaction between chemicals, but probably nothing to lose sleep over. Just keep running the filter and you should clear in a few days. If not, add a dose of Clarifier.

  31. Pool was green. Went thru a series of chemicals That was recommended. I vacuumed the pool this morning and it turned cloudy. A little less green but not blue. Chlorine is high and PH is very low. Should we go ahead and add PH or just wait it out another day?

    • Keep your pH low, unless it is below 7.0, then bump it up. Keep filtering the pool, 24/7 if possible. A Clarifier could help your filter trap the small particles.

  32. I shocked my pool heavy yesterday based on my local pool store’s instructions. It had gotten pretty green from algae so I vacuumed to waste to give the walls/floor a good cleaning (it was still green after but lighter). Pool store tested my water, PH came back at an 8.0 and chlorine was low. They had me put in roughly 62 ounces of ph reducer (pool is approx 28k gallons), wait an hour then put in 4 gallons of shock, wait another hour and then another 4 gallons of shock. I ran the filter all night and the pool looks exactly the same aside from being able to smell the chlorine coming off it (kinda like a hotel pool). So I checked water myself this time and PH was still an 8. This time I just went off the instructions from the PH bottle itself which said to put in 70 ounces of reducer and retest in 2 hours, which I did. PH finally dropped to where it should be but chlorine is showing as a bright orange when I use my test kit (according to kit chlorine should be yellow, it doesnt even have orange as a possibility). If I keep running my filter should my chlorine level drop down in a couple hours/clean out the green in my pool or should I start looking at other options?

    • Hi Cam, the orange is just very high chlorine, could be 10-20 ppm, but if pool is still green-ish, you need more. Keep running the filter, 24/7 if possible, but it may take several days or a week perhaps, until chlorine testing is yellow again. Keep the chlorine high and pH low, and run the filter, and keep vacuuming to waste, brushing and skimming daily. You’ll get there soon! 🙂

  33. Connie Bergman

    I have a 20,000 gal inground pool. After heavy rain last night. Having a chlorine lock for weeks. pH showed high today so did 1.4 lbs Ph decreaser. Several hours later I decided to throw in 2 (1lb) calcium hypochlorite pouches. My PH monitor now says pH is high. It’s been several hours since I added shock. How soon can (or should) I add more pH decreaser?

    • Hi Connie, you can add more pH decreaser now if needed, no need to wait. You may want to also have a test kit, so that you can calculate ‘acid demand’ tests, and know exactly how much pH chemical to add.

  34. Kelly Kosloske

    I was given a pool starter kit for our new pool and put it all in at once. There were no directions and now after reading online, I think I’ve made a big mistake. Have I completely ruined our pool water and how do I fix it?

    • Hi Kelly, not a big mistake, don’t worry about it. You may only have deactivated some of the chemicals (Stain/Scale, Algaecide), with shock chlorine levels. Typically one should first balance pH/Alkalinity/Calcium Hardness, then first add the Stain chemical and allow to circulate. Then add the shock chlorine after 8-hours or so. Then Clarifier on day 2, then Algaecide on day 3. Then tablet chlorine on day 2 or 3, and keep tablets in until closing, to maintain a constant and consistent chlorine level.

  35. Angelita Salinas

    If i put a clarifer 30 mins ago. Can I now put dry acid. Or how long do I have to wait?

    • Yes, you can add it after 30 minutes. It’s best to wait some time between chemical additions, but no need to wait for hours, just 15-45 mins is enough time, if the pump is running to circulate.

  36. Hello. So this morning my son accidently did a backwash on the sand filter then turned it right back to filter….so that put green stuff all in my pool. I treated with algaecide and clarifier but testing chemicals I already know my stabilizer is low. Can I go ahead and add the stabilizer or should I wait?

    • Yes you can add the Stabilizer now. Be sure to always shut off the pump first, before turning a backwash valve handle.

  37. ALFRED GANGEMI

    I thought I posted, but didn’t get an email and I don’t see it, so apologies for a double post.

    How does one maintain low CYA with the 3 inch chlorine tablets? How many tablets to add? What setting for chlorinator?

    I have a Hayward CL200 inline chlorinator with the setting now at 5, and I typically about in 6 tablets every week or so. My CYA hit 109 the other day with all other readings good. Now my readings are the following:
    TCL: 5.52
    FCL: 6.58
    CCL: 1.1
    pH: 7.1
    Alk: 78
    CH: 181
    CYA: 96

    I just added 10lbs of Alkalinity Increaser into 20k gallon pool, so that should address the Alk and pH. I just bought a Superior pump to help with draining of the pool to lower CYA.

    Is this going to be common, draining the pool, to maintain low CYA?

    Thanks again!

    • Hi Alfred, some tips to reduce cyanuric buildup:
      1. Use fewer chlorine tablets. Not sure if your current 5.5 ppm chlorine level is normal? Use less tabs 3-4 tabs/wk, and aim for 1.5 ppm.
      2. Use Nature 2 mineral purifier. As a supplement, which will allow you to run chlorine levels at .5-.7 ppm, assuming you have an effective filter.
      3. Drain some water each year, just 3-4000 gallons.

  38. Atara Klein

    I accidentally added scale and staining prevent instead of remove last week. It instantly made my pool cloudy and now I can not remove the cloudiness. What do I do? I have such a clear looking pool before

    • Hi Atara, sometimes stain & scale can cloud the pool – I would recommend shocking the pool with chlorine or non-chlorine shock, and increasing filter run time to near 24 hrs daily. After 36 hours or so, add a Clarifier, following label dose closely.

  39. Hi, our pool was not holding chlorine, I went to the pool store today and after testing the water we needed to add two gallons of stabilizer. I added both gallons to the skimmer but missed the directions where it said to add one and then wait two hours to add the other one. Is my pool in trouble ?

  40. I have a 15000 gallon gunnite pool, not paying attention today I added 40oz of conditioner then added 16 oz of no pho’s. After the fact read that noPhos should not be used when adding conditioner. What to do here?

    • Heh – well you found the right blog post! What likely is the result is that the effectiveness of the NoPhos will have been reduced. Continue with the NoPhos process as described, and then test phosphates again to see where the level is, and treat again if needed.

  41. Karen Crenshaw

    Trying to increase chlorine after treating for metal stains. What’s my best plan of action? Saltwater pool, I have it turned to about 80% but it’s not doing much after 2 days. CYA is low but I’ve had to balance alkalinity and ph then increase hardness and I’m afraid to add CYA the same day as calcium hardiness increaser. Help! Thanks in advance!

    • Hi Karen, you can go ahead and add the cyanuric, well now it’s been a day later anyway! Sorry, I’m a bit backed on these questions! Almost done now! If your chlorine level is very low, add some granular chlorine. It’s always a good idea to keep some granular (pool shock) on hand with saltwater pools. You never know, when the pump, filter or salt system will let you down, and it’s best to use shock for shocking the pool, even though some salt systems have a shock function or button, it is very slow to work, and it puts a heavy workload on the salt cell.

  42. Sarah Perry

    I added shock to my pool tonight.. not knowing that my husband had just added clarifier.. I know it’s not a good mix .. what can I do?

  43. Inherited an above ground pool with our home. After topping off the pool with well water our water became cloudy. We had the water tested and it came back with too much copper. We’ve had a metal sequestrant in the filter for 3 days now and today we added pool clarifier. We thought each line on the bottle was one ounce but it turned out to be two so we think we may have added double the dose. Is this really bad? Is there anything we can do right now to stop it from getting worse? (Also we’ve been running the filter for 5 days straight now. Nothing seems to be clearing the pool up) thank you! We have a pool party scheduled for next week and we’ve been dealing with this for three weeks! 🙁

    • Hi Natasha, metals are not normally a cause of cloudy water. No problem with doubling a sequestrant dose, but over-dosing with Clarifier can have the opposite effect. You can redose again (weekly) with Clarifier, after 3-4 more days. Keep running the filter and keep a low pH level 7.2-ish, and a high chlorine level 2-5 ppm. If your filter is small, or a low performer, it could be the biggest contributor to cloudy water. We have a few blog posts on how to improve filtration performance, that you may want to read. If the filter media (sand or cartridges) are very old, start with a Filter Cleaner, or replace the sand or cartridge.

  44. New to the pool game. Need some advice. Can I add dry acid and Hardness plus at the same time?

    • Yes you can, just one at a time, and perhaps added to separate parts of the pool, separated by a few minutes, but yeah…

  45. John Brennan

    I mistakenly added chlorine & clear pool algaecide together and caused a nasty reaction! Have I damaged anything? Or will the hot tub be safeto use after a period of time? Or will I need to empty & re-fill the hot tub? Grateful for any suggestions!

    • Hi John, it can be important to use only Spa Chemicals in a hot tub, as they are formulated and labeled and packaged for spa use. Chlorine and algaecide won’t normally react, when in water together (if they ever touch outside of water however, they can ignite into a roaring violent fire). Normally, when shock chlorine and algaecide are added at the same time, high levels of shock will destroy the algaecide. See how it goes for a day, if it is still looking bad today, go ahead and drain, yes.

  46. I miss understood the instructions and add the clorine conditioner and water clearifer at the same time to my aboveground pool. Will ot harm the vina?

  47. Jan Schwarz

    Hi. We have an in ground pool – 20,000. It wasn’t covered in the winter and of course collected a lot of leaves and gunk. It looked like a green swamp. I have slowly gotten it back to a pretty blue, but so cloudy you can’t see the bottom. The PH is low. Also the hardness is high. Chlorine is the low range and free chlorine almost nothing. Alkalinity is OK. I don’t know whether to raise the PH and then super shock or shock and then raise the PH. I also bought some non chlorine shock. Not sure what to do. Any advice would be greatly appreciated!!!

    • Ok, real simple – keep the chlorine high and the pH low, and run the filter nearly non-stop. Add Clarifier, per label dose, that will help too.

  48. I am new to taking care of a pool. I have a 3,800 gallon pool without a cover (it had to be shipped so still waiting on it as well as the 6-way test strips) Two days after filling up the pool I added the initial amount the bottle suggested of liquid pool shock. It turned the water green. I waited a few days and it went away after washing the filter 3-4 times a day. I added pool shock again last night after a rainy day the day before and it turned the water green again. There is also a chlorine floater with a tablet in the pool and the white part of floater now has a burnt orange film on it. Any help is appreciated. Thank you.

    • Hi Shannon, How much are you adding of the chlorine? I’m guessing about 2-3 cups? Now, liquid chlorine does have a green color, but does not normally turn pools green, but it could be knocking some minerals or metals out of solution, like copper. And the burnt orange film, oh boy, I’m not sure!

  49. Help! My pool is brown, I had it blue, but cloudy, but no matter how much shock I was putting in, I couldn’t get chlorine to read, it was really green when opened it, and I did the metal magic and algae, and vaccuumed to start. Then it started to turn green again, so I got the stronger algae treatment and put that in, vacuum/back washed and then added shock, it got less green, but more brown(we also have a well), I got my PH and Alkalinity to normal, but low and the pool store told me to add metal magic and vacuum/backwash and chlorine. I added a little more water, and tested it, still ok levels except for chlorine, so I put in metal magic, vacuumed/back washed the next day and then added shock, but my pool is still brown, although the chlorine is high, PH is ok, a little low, but now my alkalinity dropped, What do I do now? I just want a clear blue pool! Please HELP! I keep asking and doing what they tell me, but it’s not working!

    • Mollie, I’m going to ask about your filter. It may be under-performing. Does brown backwash water come out? Does the filter pressure increase and flow rate slow? Often we think so much about water chemistry, we can be blind to filtration and circulation problems. Are you running nearly 24/7, the filter? Is the filter media (sand?) old or not trapping tiny particles? Try a Sand Filter Cleaner, Try Pool Clarifier, and consider replacing the sand, or if the filter is very small, it may be fine for keeping clear water clear, but not big enough to return a pool with problem water, back to clarity, but keep at it! Low pH, High Chlorine, near constant filtering, and keep the pool vacuumed, skimmed, brushed.

  50. I bought a house that came with the pool so I am brand new at this..
    How can I tell how many gallons my pool is? Also, I had the water tested and needed several chemicals. I did not know until AFTER adding all the chemicals together that I’m not supposed add them at the same time. I added 10 lbs of alkalinity up at the same time with 19 lbs of hardness plus, then 5 hours later another 19 lbs of hardness plus with a gallon of water conditioner. I know NOT to do this again but should I be worried?? Or just let this ride out and keep testing the water

    • Hi Jessica, likely there was no problem with adding those chemicals at the same time. One should never mix dry chemicals together, but if you add one chemical into the pool, and a few minutes later add a second, and then third chemical, in most cases nothing will happen. In general, it is best to give them time to make their adjustments, without the influence of other interactions or reactions happening. When i want to add more than one, I commonly will just add them at opposite ends of the pool, and just a few minutes apart. To CALCULATE POOL GALLONAGE: the formula is Length x width x average depth x 7.5 (rectangular pools), or x 5.9 for oval ended or round pools. Average depth is just the median depth if you have both deep end (8 ft) and shallow end (4 ft) – average depth = 6 ft. For flat bottomed aboveground pools with no deep end, the average depth is just the total depth.

  51. I have a 13,000 gallon above ground pool. I just replaced the liner. We filled the pool up with well water which has a lot of iron. I added a whole quart of stain/scale remover. I have been running I gotta my filter 24/7 since filling and adding the stain/scale remover. I have cleaned my filter every morning(3 times) I still get a quite a bit of orange on my filter. When is it safe to add other. He I also to make my pool clear? I can now see the bottom but it is still A bit cloudy and a greenish color.

    • Sarah, you should get the chlorine level up, and also be sure pH is not high, or above 7.6. Add more of the Stain & Scale, and follow the maintenance dose treatment, to add replenisment amounts each week or two, as the chemical depletes in the sun, a little bit each day. Also, use a Clarifier every 5-7 days to help the filter trap the metal ions. It may take another week to clear completely. A new filter cartridge would help, or you can wait until pool is almost clear, then replace the cartridge with new. Keep the chlorine high and the pH low, as I tell all my readers…

  52. sharon majers

    i have been fighting chlorine lock for 2 months. I have drained much of the pool over time and I have my cyanuric acid levels at normal. Still no chlorine. I am using chlorine tablets with no cyanuric acid. At the same time I am having metal staining on my vinyl liner. I’ve used ascorbic acid and then Metal Free. It looks great for 4 days and then the stains come back. I’ve tested the water and my metals are at ok level. My pool is 32000 gal. with a sand filter. Right now I have stains and no chlorine. my phosphate levels are at about 1000 after 3 bottles of phosphate free. help please.

    • You have got some problems! 🙂 For chlorine lock, try a super-duper quadruple shock, 4 lbs per 10,000 gals, or 13 lbs of shock, all at once, with a nice low pH of 7.2-ish. For metal staining, keep adding weekly maintenance doses of Metal Free, per label instructions. And phosphate levels are still high, recommended to be below 300 ppb. If you are using Clarifiers, make sure they do not contain phosphonic acid, a form of phosphate. Let’s try a different remover, look at SeaKlear phosphate remover.

  53. I have a 10,000 gallon pool. The water was perfectly clear but the pH was very low (6.4). I was instructed to add 12 lbs. of alkalinity up and recheck the pH. I added the alkalinity up and the pool turned cloudy with a blue film on top. I checked the pH, it was still low. I was instructed to add 1 lb of pH up which I did. The pH is still low and the water is still cloudy with a blue film on top. Any ideas?

    • HI Donna, not too uncommon, for large additions of base to cloud the water temporarily. Just keep filtering (24/7 if possible), and using a Clarifier can help. As for the blue film… not sure about that, unsure what that might be, but the same advice applies… no worries!

  54. Nicholas

    Hello there. New to Pools. Picked up what Ibthought were 2 bags of PH Up. But 1 was up and 1 was down. Almost identical bags. Added the PH low first (thinking it was up). Checked a few hours later. Level was so low. So I added more. But this time I was actually using up. Is this serious?

    • Naah, sounds like they should just cancel each other out, and should have brought you back to near where you started.

  55. Theress Clemens

    I have used 9 lbs of shock. CYA is stable.thank you.

  56. Theresa Clemens

    I have a 10,0000 gallon pool. It was cloudy upon opening. It is clear, but not holding chlorine. I have taken the filter apart and cleaned it, drained a third of the pool. Still 0 chlorine levels. Used Phosfree last night, now my filter pressure keeps rising. I’ve owned a pool for 30 years. This has never happened before.

    • Hi Theresa, either you have zero cyanuric acid (Stabilizer, recommended 30-50 ppm), or you are not adding enough chlorine, or using very old chlorine without potency, or there is something invisible in the water like Nitrates that is consuming the chlorine. Some call it “Chlorine Lock”, and the way to get rid of it is by super shock, a quad-shock, of 4 lbs per 10,000 gallons. The phosfree will raise filter pressure as it removes phospates from the water. It is also known to make water cloudy in some cases, but a good product to use, if phosphate levels are over 300 ppb.

  57. Hello. My pool is is about 35,000 gallons. I had some metal staining and did a whole process of lowering chlorine, adding ascorbic acid and then a metal sequestrant. The stains lightened but didn’t completely go away. I slowly started adding the chlorine back in the pool. My local pool company told me my phosphates were high at 600 and recommended phosfree. I added the recommended amount based on my numbers. The pool completely clouded up and now has white foamy bubbles at the surface. I ran the filter consistently for 3 days and it only got worse. I added a flocculant and it didn’t work. I blind vacuumed the pool to waste to remove the dirty water. That helped slightly but still cloudy. What steps should I take next to clear the pool? Thanks in advance.

    • Brian, just keep at it. Phosfree can occasionally cloud pool water. Add another dose of Clarifier, being careful not to over-dose. Run the filter 24 hrs per day, and clean only when the pressure gauge rises at least 5 psi. Did you raise the chlorine level back up? Try to keep the chlorine high and the pH low, and filter the water constantly.

  58. Sandra ford

    My husband added chlorine ph plus and algeacide to the pool all at the same time. What is the worse scenario and do we need to start over

    • Maybe nothing wrong, however chlorine is more effective at a lower pH level. Shock chlorine will destroy algaecide. Not a big deal, go easy on the poor guy! 🙂

  59. I am getting a lot bit of scale on plaster pool walls. Not sure if the pool company added scale free when they opened it. What do you suggest I do get rid of it?

    • Most service companies do not add a Scale Free chemical when opening a pool. That is what I would start with, Scale Free or similar product. Also make sure the pH is not high, which can cause calcium to precipitate out of the water.

  60. I accidentally forgot that i was supposed to add clarifier 12 hours after 2lbs of shock and i had my husband just toss it in and I just now remembered. So what is that going to do to my 12,500 gal pool.

    • That will be fine, no problems, I suspect.

      • I woke up this morning and its extremely cloudy murky. How should i correct this to make it clear and settle so i can vacuum?

        • And whats the difference between flock and clarifier?

          • FLocculent will attach itself to the suspended particles and sink them to the bottom, for vacuuming, to waste. Clarifiers, create larger particles but without weight, so that they stay free-floating, until they are trapped in the filter.

        • Run the filter, you may not be running it long enough each day. Add chlorine, you may not have enough in the water. Use Clarifier, that can help a small, undersized filter.

  61. Nicole Eaton

    Have a 24 in round 13,500 gallon above ground pool with sand filter. Bought brand new last year, pump everything brand new. We cannot get our pool clear. It is very cloudy, milk like. We took water sample to pool place, they told me to use 8 gallons of liquid shock, stabilizer and a whole bottle of copper 7. 3 days later pool still looks the same. Not to mention a week ago we used 8 gallons of shock per pool place and nothing, sun evaporated all the chlorine. We have cleaned the pool, scrubbed the liner, vacuumed, keep skimmer clear, backwash filter. I hate to drain 13,500 gallons of water and refill it because we can’t get our water clear. Pump everything working good, good circulation.

    • Nicole, how many hours per day are you running the filter? I would recommend 24 hours per day until it clears, the 12-hours daily after that, or 24/7 if 12 hours does not keep the water clear. Also, use a Clarifier to help our your filter. Do you have stabilizer in the pool to protect chlorine from the sun? After the 8 gallons, are you chlorinating every day? You need to have a constant and consistent level of chlorine in the water, 24/7, and a good, low pH level, in the range of 7.2-7.6.

  62. Janice Shelton

    We recently purchased a small inflatable Coleman hot tub…holds 250+/- gallons. We are so unsure what chemicals to add without fear of a fire. Our ph usually runs too high. Can we put PH decreaser and clorine in at the same time ….or what do you suggest?

    • Hi Janice, don’t worry, nothing will blow-up! Or catch fire! Although I could tell you a story of the time that algaecide and pool shock met, in the back of my pickup truck – that was quite a fire. And chlorine and pH decreaser, another story of a hotel evacuation, when they were mixed by an inattentive lifeguard… but for your little spa, you’ll be fine. 🙂 Now, yes you can add pH decreaser and chlorine at near the same time. I would add the acid first, let it mix around for 30 seconds, then you can shock the spa with a chlorine powder, or you can use MPS, non chlorine powder.

  63. is it possible that my pool guy can add chemicals that will damage my filter grids in order purchase more from him?

    • Hi Tony, if you were to add chlorine granules or dry acid to the skimmer, that could have a corrosive effect on DE grids. I’ve never tried it, so I’m not too certain of the effects, but it would likely be a bad idea, especially if done repeatedly, I could see it making small chemical burns in the grid fabric. But if added directly to the pool, it should pose no problem.

  64. Clarissa Grossmann

    New to pools and I have a 12′ ft above ground pool with well water. It’s been clear until heavy rains started last week and now it’s a mess. A few days ago I did algaecide and today I shocked. Still cloudy, so I’m wondering if I just need to change my filter? The cloudiness persists no matter what I have tried.

    • Hi Clarissa, have you tried running the filter longer, or up to 24 hrs daily? If so, yes change the cartridge. If you have an Intex style pool, they recommend a new filter cartridge every 30 days (or at least by 90 days). Use of a Clarifier chemical can help small filters. Keep the chlorine high and the pH low, and run the filter non-stop. Add Clarifier, but be careful not to over-dose, only add the recommended dose. Redose in 5-7 days if needed.

  65. Hello, I’m new to this. 4800 gallon pool, chlorox testing kit/app shows zero chlorine (including free), zero stabalizer, high alkalinity, low pH. I have mauratic acid, liquid chlorine, powder pH up packs, chlorox stabalizer, all sitting in front of me. Could you tell me in what order to use these products & the time in between adding them please!! This pool is out of control from all of the rain & I don’t know where to begin!!

    • Hi Kelly; Backwash the filter and then add the stabilizer, following directions. Then add the liquid chlorine, if 6% bleach, add 1-gallon, or the entire bottle to the pool. And after a few days the chlorine will return to normal, then use tablets (best) or liquid if you must, to maintain a constant and consistent chlorine level of 1-2 ppm, as verified by your test kit/strips. low pH and high alkalinity, not necessarily a problem, but be sure pH is above 7.0, ideally in the 7.2 – 7.6 range. If outside of that range, add pH Up or pH Down chemical to the pool, to adjust the pH. Test again in 4-24 hours to be sure you hit the mark.

  66. Brand new to the pool ownership. I did a test strip when I got the pool filled to check my ph and alkalinity. To adjust, I used pH Up and have two chlorine tablets in a floater. The pH Up was added two days ago, and The chlorine floaters were added yesterday, My question is, when can I add shock?

    • Hi Jessica, go ahead and shock the pool, no need to wait. Many people shock at night, or early in the am, when the sun is not beating down, which degrades chlorine a bit, but anytime is really OK.

  67. HELP!! My pool is brown. I have called my pool store and gone there in person and have done everything they have told me to do and it doesn’t help! I followed what they said and it keeps turning brown, so then I read on the net, went there again and tried again. We haven’t added any water recently, because we haven’t needed to, but we have a well, so when we filled the pool we put metal magic in to remove the iron. Once the first incident happened, we added acid to clear it up and start over with the chemicals. They said to add Alkalinity and get that at a good reading, I did that, then I added the PH up and got that to a good reading, once that was good, I added some zip chlor and two chlorine tablets to the water and the next morning it was brown. I have also done shock instead of zip chlor and the same thing happens. Everything was reading normal, a little high on the chlorine, but this keeps happening every time I add chlorine, the water was clear but cloudy after the Alkalinity and PH but once I add chlorine it all goes to crap. Any recommendations on what I am doing wrong or need to do? Can I put anything in to clear up the brown without starting over with the acid and then the chemicals again, we are spending way to much money trying to get this to work. Thanks

    • Hi Mollie, the shock is causing the metals (iron, mostly) to drop out of solution, so… let’s stop shocking the pool. You can try to reabsorb the metals using a sequestering agent like Metal Magic or our own Stain Away. Along with lots of filtering and a good Clarifier. There is a product called CuLator, which is the only product to actually Absorb and Remove metals from the pool, by means of a small pouch that is replaced every few months. Otherwise, I guess I’d go the acid route one more time, but don’t shock the pool, just slowly start using tablets, and be sure to keep up with the Metal Magic – it degrades and only lasts for a few weeks after initial dose. Keep adding it for continued protection, following the maintenance dose guidelines.

  68. stephen mcgeorge

    Can you shock the pool and add clarifier at the same time? If not how long do I wait. Also can I add a stabilizer the next day after shocking pool? Thanks

    • Hi – thanks for the Great Question! Right – you should Shock First, but wait to add Clarifier, until chlorine levels are at least below 10 ppm, or 5 ppm if possible. High chlorine levels can disrupt the polymer chains used in many Clarifiers. The stabilizer you can add the next day after shocking yes, or before, either one.

  69. I added two bottles of Ph down and I think it etched my pool. Is there a fix? We spent weeks brushing it smooth when,it was installed, just for me to etch the plaster and make it rough.

    • Hi Michael, can you get under water with a mask and maybe a magnifying glass? (seriously). To see if you have deposits on TOP of the surface, as calcified nodules, or if you are really feeling etching or corroded areas, where there is a depression from material that is now missing. Nodules can be sanded off, but etching… well, not much you can do, but sanding with a sanding block can help reduce the roughness and smooth it out somewhat. In severe cases, you could lower the water, and sand it with a power sander or grinder, to even out the highs and lows. Don’t beat yourself up too much, it may not have been a good mixture, if it can’t handle a few pounds of dry acid being thrown on top of it! Lots of mix and application factors can produce soft spots in the finish that erode more easily. If very new and fresh plaster however, some softness is to be expected…

  70. Stephanie Herb

    Hi I’ve got metal in my water and have got Metal Out and lowered my chlorine to zero as the instructions said. I now have green algae growing. My question is can I add algaecide along with Metal Out or should I wait a day.

    • Yes, add the algaecide at the same time, or actually wait a few hours then add the algaecide. Then immediately add tablets to begin bringing up the chlorine level. If algae is getting real bad, put the metal treatment on hold, and shock the pool. When blue and clear water is restored, resume metal treatment.

  71. Hi I seem to have made mistake of mixing wrong combination of pool chemicals. Fortunately no disaster but the water is now cloudy for 3 days. I got water analysis done at Leslie’s and only thing which came up off was high alkalinity which they recommended 2 lbs dry acid to reduce alkalinity. The water I’d still cloudy. I will get another analysis but is there a way to fix cloudy water or only solution is to empty and refill pool?

    • To fix cloudy water – I would look away from chemistry and look towards your filter. Are you running the filter long enough each day? Is your filter (and valve) working properly, or is it bypassing water unfiltered? Is the filter media old and tired, or is the filter undersized? I would first be sure that filtration is top notch – then, make sure the water chemistry is balanced, then make sure the chlorine level is proper – all important for clear water. You can then use a Clarifier to help your filter by coagulating smaller particles into larger, more easily filtered clumps. Aluminum Sulfate, or “Alum” can also be used to clear a pool, to “Floc” a pool, using 3-4 lbs per 10K gals, but you must be able to vacuum to waste, the following day.

  72. Hi – I mixed Total Alkalinity and Calcium Hardness within 2hrs of eachother. My water readings are coming out perfect BUT I’m getting these hard green crystalized pebbles at the bottom of my pool now. If I don’t run the filter more seem to show up. Any ideas what this is how to treat it??

    • Hi Ken, not sure what that is, perhaps it is blown-in or thrown-in. High pH and high calcium can cause calcium nodules to form, but they are not green, unless there is a very high level of copper in the water perhaps, or algae…? hmmm, not sure Ken!

  73. I accidentally emptied bags microfloc shock.(non chlorine shock) in a bucket containing alkalinity increaser. Will those two chemicals react and how do I dispose of it needed

    • Hi Keith, normally Alkalinity increaser will not react (too much) with non-chlorine shock, dispose of it in the pool, as soon as possible, however.

  74. Louanne Payne

    I desperately need help with mustard algae. Up until this year, the pool has been easily maintained with a max of 3 green algae blooms. We opened the pool on May 7th and within 1 week brown sandy streaks and blotches started forming on the shallow end floor and all around the crease where the floor meets the wall in the deep end. It’s a 39,000 gal pool. I have a VS pump that I leave on 24/7 running at 50 gal/min (2400 RPM). The filter is a 72 sq ft DE grid filter (installed this May). I have been keeping 3 floaters in the pool with 4 of the 3 in. trichlor pucks in each of them because I am keeping the SWG off while adding chemicals. I had been adding 12.5% liquid chlorine shock to maintain a free chlorine (FC) level of 15 while keeping the pH around 7.3-7.6. The TA has drifted down from 90 to 70 and the CYA dropped from 30 to 10. And…my phosphates have increased from the baseline of 200 to 750. So far, the test for nitrate has been negative. There are no metals in the pool and no algaecides have been used. I have been brushing the whole pool (skimmers included) every day…sometimes twice a day for a week and sanitizing any hoses, poles, brushes, etc. I also removed the ladder from the deep end, vacuumed to waste 3 times, and I have back-washed the filter 3 times. It seemed to disappear in 1 – 2 weeks, but as soon as the FC fell below 7 PPM, white sandy patches showed up in the same places in the shallow end only. I repeated the process and every time the FC neared 7, I would see the same patches again. A week ago (around July 2nd), I decided to switch to Cal-hypo 73% since my CH was 130. The patches now show up at a FC level of 12 and they are darker, in the original spots and spreading! I am SO frustrated! I would prefer to not use metal algaecides and I am nervous about trying NaBr. Help? Thank you.

    • Hi Louanne, here’s a few things to try – 1. Run the pump at a higher speed for a 4-6 hours per day, during the sunny parts of the day. At 50 gpm, it would take 13 hours for a complete turnover, and although you run it 24/7, having a higher flow rate, even if running the pump fewer hours per day, may help. Maybe try running at full speed (3400 RPM) for 8 hrs daily (sunny hours), and then drop to 1750 RPM for 16 hrs daily. Secondly, I would treat with PhosFree or other phosphate remover, to bring it down to 200 ppm or lower. Third, I would open up the filter and pull out the grids for a complete cleaning and inspection, looking for holes that may be passing DE powder into the pool, or cracks in the manifold, or a missing internal air relief strainer or ‘sock’. Fourth, raise the cya back up to 30 ppm, by adding approximately 8 lbs of stabilizer. I’m with you on the NaBr (Yellow Out), if you can avoid it, I think that would be best.

      • Louanne Payne

        Thank you for helping me out!

        Is it possible to change a couple of things slightly without risking a positive result? My Pentair Intelliflo Variable Speed pump has a max flow of 3450. Is there a lower value than 3400 you would recommend? Also, should I clean and check the filter before adding a phosphate remover or do the filter before the phosphate treatment? I GREATLY appreciate your help.

        • Hi, oh yes, I meant 3450, or max-speed but said 3400 RPM by mistake. I would check the filter first. Backwash it really well, open the air bleeder, remove the clamp band and pull out the grid assembly, where you can hose it off completely, and inspect the grids for voids/tears, and the manifold for cracks. There is a small o-ring on the standpipe that the manifold fits over, be sure that it’s in good shape, and lube it when putting the filter back in place.

  75. So, say I accidentally mixed shock, stabilizer, and algicide and caused a small fire. Would that pool water still be safe to swim in after the small fire?

    • Hi, sure i think it would be. As long as water balance and chlorine readings are normal. Thanks for the comment, scary stuff!

  76. Hi.
    I need help figuring out what pump to buy.

    My pool dimensions are 25 long by 10 wide (kidney shaped) & it is 3′ deep in the shallow & almost 5′ in the deep end.

    I also have a million trees that drop leaves & flowers & even berries into our pool.

    I was told at a store that getting too much of a motor or too heavy duty a pump I will have just as bad effect. We have found great success w/ a pentair sand shark auto cleaner but after a recent hail storm our motor just isn’t working how it used to.
    Tina from Texas

    • Davy Merino

      Hi Tina, the way to select a pump is to match the pump flow rates (in gallons per minute GPM), to the filter design flow rate. Look on your filter label for this information, or find it on a product page (where we sell the filter that you have). Then, look for a pump that will produce that level of flow rate that works best with your filter. Too much flow is much worse than too little flow, in terms of filtration – but you need enough flow to ideally, filter all of the water in the pool, in an 8 hour period. For example, a 50 gpm pump can pump 50 gallons per min. or 3000 gallons per hour. In 8 hours, it will pump 24000 gallons. Your pool is much smaller, if your dimensions are correct. If your previous pump make/model/size worked well, it is easiest to replace with the same. If you want more flow or need more flow, proceed cautiously, to not go too big. Your pump, which stopped working “how it used to”, after a hail storm… could have a clogged impeller, or an air leak in front of the pump, and could possibly be repaired instead of replaced.

  77. Phil Gilmer

    Hi, I have had issues with my (pebbletec) pool turning blue along the tiled water line as well as the creepy. I’ve concluded it’s too much copper (from algaecide and copper trichlor additive) and which is leaching out somehow? Or maybe you have a better notion? Thanks!

    • Davy Merino

      Hi Phil, copper would be a good guess, especially if it is a stain, and not a gooey, oily deposit. The only other guess would be some blue substance (paint?) that was thrown in the pool by a prankster. Not much else makes a blue stain. You can test the water with a copper test kit to confirm. Pouring an acid mixture from a flower watering can, or spraying from a spray bottle would be the trick to try and remove the stain – lower the water first, then readjust pH afterwards.

  78. Josie Peebles

    Hi,
    Having problems with a cloudy pool and want to discuss with Dr. Pool…what is the email address?

  79. Hi Dave,

    I have an interesting senario for you!!! We went away on holiday last week. We left out 18′ round above ground pool on a timer for the sand filter for 6 hours a day from 10-4. It had its solar cover on the entire time. Our neighbours said it went green about 5 days after we left. After checking levels, free chlorine is high, stabilizer low, and pH low to normal, alkalinity normal and hardness normal. Pool has a huge algae bloom. What do I do??? From what I read, it seems impossible to have low stabilizer and high chlorine! What is going on and how do I fix it!!!

    • Davy Merino

      Maybe a power outage, from storms, could’ve shut off the pump for a few days? The solar cover on top, maybe not the cause, but could aid in an algae bloom. Algae normally can’t grow with VERY high chlorine levels, unless phosphates/nitrates are very high, but a pool can still be green with 5+ ppm of chlorine testing… The filter could’ve become dirty and clogged, or if the pool was being maintained (by the neighbor?), they may have reinstalled the filter incorrectly, or did something incorrectly, to reduce filtration, or sanitation, or both. If the pool is still green, add more chlorine, until it turns a blue/gray color, and filter 24/7 until clear.

  80. I have a 650 gallon pool. How much shock/etc, and how often, should I be treating it? The kit I bought only explains amounts for larger pools. Also, should we keep the pump running constantly? We’ve been just running it for a few hours here and there or while we’re in it. Thanks!

    • Davy Merino

      Hi, most chemicals give dosage amounts per 10,000 gallons. You can multiply treatment dosages by 0.065 to obtain your dosage amounts (for a 650 gallon pool). You can also use poolcalculator.com, which I find useful. Your filter is very small, and I would run the filter much longer personally, like 12 hours per day, on a small plug-in timeclock, or at least 8 hours per day. I like to turnover the water twice, (a turnover is when all 650 gallons have been filtered). Depending on the pump flowrate, that could take some time. It is a balancing act of filtration, sanitation and circulation, that will keep your water clear and healthy. If you don’t run the filter enough, you will need more chlorine, or vice-versa.

  81. I need help with my chemicals? My pool water is cloudy, it’s a 5000 gal above ground steel
    Frame pool. I am emptying about half of the water and refilling it with new water, how do I keep it from happening again? Need help?? Thank you

    • Davy Merino

      Hi Ed, it could be your filtration, and not your chemicals, or a bit of both. Your pool may have a very small filter, and when it gets really hot outside, you may need to run it 24/7. You may also need a new cartridge, they only last a few months – using a clarifier could help your filter out. Second tip, keep the pH on the low end, around 7.2-7.4, and keep the chlorine at 1.5-3.0 ppm. If the sun burns it off too fast, add 1-2 lbs of stabilizer (cyanuric acid) – as a sunscreen (but check level first, needs to be 20-50 ppm).

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