Why Is My Pool Cloudy?

[social_warfare buttons=”Facebook, Twitter”] Whether it is cloudy judgments, cloudy weather, or cloudy pools, ‘cloudy’ isn’t a word that is typically used in a positive manner. So when it comes to a cloudy pool, you want to address the issue ASAP. Failure to address your cloudy water in a timely manner can hurt your pockets and your patience.

When we come across pool owners with cloudy pools, they always want to know three things: Why is my pool cloudy? How do I get rid of my cloudy pool? How can I prevent this from happening again? These three questions present the perfect thought process for clearing up a cloudy pool. Before you can fix the cloudiness, you need to determine what caused your water to become cloudy in the first place. Once you figure out the root to the issue, then you can take action to remedy it. Finally, you have to educate yourself in preventative measures to ensure your pool remains healthy.

Depending on the severity of the cloudiness, returning your pool back to its healthy state can take a couple of days to a few weeks. Let’s figure out the root to your cloudiness.

How Cloudy Is Cloudy?

Before you can treat your pool, you first have to determine why your pool is cloudy. But, how cloudy is cloudy? There are different levels of cloudiness and most often the cause determines the appropriate treatment. Let’s discuss the degrees of cloudiness.

Flat/Dull: The water may be blue, but it doesn’t sparkle. It doesn’t have the shine.

Hazy: The pool water isn’t clear anymore. You can still see the bottom of the pool but not distinctly.

Cloudy: The water has a milky quality. You can see the bottom of your pool towards the shallow end, but you can’t see it towards the deep end.

Opaque: The pool water has become so milky that you cannot see the bottom at all.


Pool Filtration

A lack of proper pool filtration can cause your pool to become cloudy. Ask yourself, are you running your filter long enough? Is your filter clean? Have you backwashed or cleaned it recently? Let’s dig a little further.

Are  You Running Your Pool Filter Long Enough?

When we ask how long you are running your filter, what we really mean is, how long do you have your pump running for? It isn’t necessary for you to run your pump 24/7 , assuming you have your pump/filter sized correct, of course. Still, you have to run your pump and filter long enough to at least filter your entire pool once. This normally takes 8 to 10 hours. Proper circulation is key to keeping your pool clear.

In your filter’s manual, the manufacturer provides turn over rates. The turnover rate is the number of gallons a particular filter will clean within a certain time. If you cannot locate the model number of your filter or your turnover rate, let us know and we can assist.

For example. let’s take a look at the Pentair Clean & Clear Plus filter specs.


For the Clean & Clear Plus filter,  Pentair provides the model number and its respective flow rate, filter area, and turnover capacity rate. From the chart, you can see that both the CCP420 and the CCP520 turns over 72,000 gallons in 8 hours. Let’s say your pool is roughly 75,000 gallons. Running your filter for 8 hours a day will not properly filter your entire pool. Over time, this can cause your water to become cloudy or even worse. To avoid this from happening, you would have to run your filter for about 9 to 10 hours.

Are you running your pump/filter long enough?

Have You Cleaned Your Filter Recently?

A pool filter is a rather passive piece of equipment. There are no electrical components or moving parts on the filter, unless you include valve handles. The filter is mainly a tank that water flows through. But there is still a complex swirl of activity going on in there, and part of that is pressure. Find the pressure gauge on your filter system to get a reading of your pressure.blog-image-pressure-gauge-200-x-200

The rule of thumb is that a reading 10 psi over normal on your pressure gauge indicates it is time to clean your filter. A dirty filter will cause your reading to spike . In most cases, the pump is still doing its job, but the dirty filter media is slowing down the return of water to the pool causing your pool to become cloudy.

If you backwashed your D.E. filter, we recommend you check the grids and manifold for cracks. Also, check the O-rings for leaks. A broken part within your filter can allow D.E. powder to enter your pool. This, combined with the lack of filtration, can cause your pool to become cloudy.

Cartridge filters should be replaced every one to two years. If you notice the bands have broken, or the pressure does not go down after cleaning the cartridges, it may be time to replace them.

If you are running your pump/filter long enough to filter your pool properly and your filter is clean and in good condition, then your filter is probably not the cause of your cloudy pool. Still, you want to make sure you continue to check your filter on a regular basis.

Chemical Imbalance

One of the basic foundations of maintaining a clear swimming pool is to ensure your water is properly balanced. A lack of chlorine or an overbearing amount  of pH or alkalinity is a sure way to offset the balance and cause your pool to become cloudy. When was the last time you checked your chemical levels? If you haven’t checked your chemicals within the last 24 hours, we recommend you do so. If you do not have a home testing kit, you can take a water sample up to your local pool store, like Leslie’s, and they can test your water for you.

Do You Have Enough Chlorine In Your Pool?

Once you have your water tested, make sure to pay close attention to your chlorine levels. The lack of chlorine is one of the leading causes for a cloudy pool. We use chlorine to sanitize the water from bacteria and other contaminants. Without chlorine, your water isn’t being sanitized and as a result, the contaminants in the water build-up and causes your water to become cloudy.

When your levels of free chlorine diminish, it forms into combined chlorine, or, chlorine that no longer has disinfecting power. If your combined chlorine surpasses the amount of free chlorine in your pool, then really, you’re not adequately disinfecting your pool and you will need to shock your pool.  In fact, if your levels of combined chlorine remain higher for long periods of time, a cloudy pool might be the least of your worries. For shocking your pool, we recommend using the SLAM method.

Make sure to check out our other blog post to get a deeper understanding of chlorine and it’s relationship with cyanuric acid.

Did You Recently Shock Your Pool?

If you recently shocked your pool and now it’s cloudy, don’t worry, they’re definitely related. However, how they’re related depends a lot on your pool. In most cases, a cloudy pool after shocking is only temporary and should clear up within 24 hours. Keep filtering your pool, add a little clarifier to help, and your pool should be clear in no time.

If after 24 hours your pool is not clear, then you may need to look a little deeper for the solution.

How High Are Your Calcium Hardness Levels?

Do you live in an area known for having ‘hard’ water? You may not be aware, but depending upon where you reside, your water may already come with a higher than average mineral content. If you live in one of these areas, you may want to avoid using calcium hypochlorite pool shock, which includes most basic brands of shock. Cal- Hypo contains high concentrations of calcium and binders that do not readily dissolve.  Shocking your pool with Cal- Hypo can cloud your water in a pool with high levels of calcium hardness.

The recommended range for residential swimming pools is 180-220 ppm.

Environmental Factors

Did you know that a pool can get cloudy simply from environmental factors? Yup, not only are you responsible for the things you put into your pool, you’re responsible for the things Mother Nature puts in, as well.

Dust, Pollen, Leaves, etc.: Sometimes, these particles are invisible to the eye, making it too small for your system to filter out. Over time, if untreated, your pool will turn cloudy.

Insects, Animals, etc.: Regardless of which state you live in,  you are bound to see insects, small animals, and other creatures in your pool. Bird droppings and other nasties produce chloramines just as human waste does and can cause your water to cloud up.

Run-off Water: During a storm, nitrates, phosphates, and other miscellaneous chemicals end up in your pool.

Treating Your Cloudy Pool

Hopefully, you’ve determined why your pool is cloudy and you’re ready for treatment. I know you have heard somewhere that there are three ways to treat a cloudy pool: clarifiers, flocculants (floc), or enzymes. But, what are the differences and which treatment is best for your pool?

How Do Clarifiers and Flocculants Work?

Let’s not forget what is happening in your water while it’s cloudy. The particles in your water are very tiny and they repel each other because of their negativity. But, when they are so small, it becomes very difficult to remove them. The way that clarifiers and flocs work is that they neutralize the electric charges so that the particles can bond with each other to become larger.  Once they bond, they grow in size and weight and are easy to filter or vacuum. Still, that doesn’t answer which one should you use on your pool.

900x900-clarifier-1Clarifiers: A clarifier is a polymer-based product that is used to coagulate (thicken) tiny particles and oils that form in your pool water. Make sure to check your water levels and adjust if necessary. When using a swimming pool clarifier, always follow the instructions on the bottle. Adding too much clarifier can make your pool cloudier. Also, don’t forget to keep your  filter running for at least 24 hours.

Works Best With Sand, Cartridge, and D.E. filters


Flocculants: Flocculants are used to sink tiny particles to the bottom of your pool, allowing them to be easily vacuumed up. Once your pool water is level, you can add flocculant to your pool. Make sure to turn your filter off for about 8 to 12 hours and do not disturb the pool during this time. Afterward, slowly vacuum your pool to waste using a manual vacuum. You cannot use an automatic cleaner for this job. If your pool clouds up during this process, take a small break to allow the particles to settle again. Once your pool is clear, backwash and rinse your filter thoroughly.

Works Best With  Sand and D.E. filters

When to Use a Clarifier or a Flocculant

The major difference between a clarifier and a flocculant is time. If you want, or need, your pool clear pretty quickly, we recommend using a flocculant.

Although clarifiers take more time, they also require a lot less work on your part. You also save money on replenishing chemicals because you don’t have to vacuum your pool to waste.

natural-chemicals-nat03122What Are Enzymes?

An excellent option to eliminate the organic material causing cloudiness in your pool is enzymes. Instead of using harsh chemicals that can be unsafe to store and handle, you can use natural enzymes to do the same thing. By adding enzymes to your pool maintenance, it eats away the dirt and oils that usually accumulate at the water line.

How Do I Prevent My Water From Getting Cloudy Again?

What’s the point of us telling you how to rid your cloudiness if we don’t tell you how to keep it away? It only takes a pool owner once to have a cloudy pool before knowing they never want to encounter it again.

Routinely check your water chemistry. We recommend to most new pool owners to check their water chemistry daily. If you’re always on top of your chlorine, pH, cyanuric acid, and total alkalinity, you’re less likely to have issues with cloudiness again. This will also prevent an algal growth.

Regularly clean your pool filter. Make sure you backwash your sand and D.E. filter regularly. Additionally, not charging enough D.E. powder to your grids can cause cloudy water. Always use the product manual for measurements. If you have a cartridge filter, make sure to inspect all of your cartridges for cracks or damages. Don’t forget to routinely check all O-rings and gaskets for leaks, as well.

Finally, make sure your pump and filter are sized properly and you are running them long enough. An undersized or an underutilized pump and filter are recipes for disaster.

67 thoughts on “Why Is My Pool Cloudy?

  1. When i opened my pool it was clear. Filled the pool and added 2 cases of liquid chlorine. Now the water is hazy. Have a new filter too. I have test strips. All levels are good but chlorine shows 0. Do i add even more chlorine? How do i get water clear?

    1. How much is two cases worth? How many tablets or pounds of chlorine did you add? What type of chlorine was it, stabilized or shock? Did you balance your other water chemistry before adding all that chlorine?

  2. I also have a cloudy pool, running the filter 24/7. It is a cartridge we use in the filter. I had the water tested and my chlorine was 22. Everything else was fine. So now we are on day 6 and it still is cloudy. Will it ever clear or is there other avenues I should look at?

    1. Why is your chlorine so high? I would stop adding shock until it comes down to a reasonable level. There is an actual section for your exact scenario in the article.

      Did You Recently Shock Your Pool?
      If you recently shocked your pool and now it’s cloudy, don’t worry, they’re definitely related. However, how they’re related depends a lot on your pool. In most cases, a cloudy pool after shocking is only temporary and should clear up within 24 hours. Keep filtering your pool, add a little clarifier to help, and your pool should be clear in no time.

      If after 24 hours your pool is not clear, then you may need to look a little deeper for the solution.

  3. We’ve had such trouble clearing our pool. It’s began as an opaque color. Even after balancing the chemicals we were still not seeing a difference. After spending hundreds in chemicals we decided to empty a third of our pool. We tested our chemicals added some ph and clarifier and in the morning we could see the bottom of the shallow end but still cloudy.
    Hardness – 250
    Total chlorine 3
    Free chlorine 3
    PH -6.8
    Alkalinity 180
    Stabilizer 50

    We got the PH To 7.2, added stabilizer and shocked the pool. Now total Chlorine and free chlorine are both nearing 10 PH is still low at 6.8 and stabilizer stayed the same at 50. Pool is still cloudy. Please help

  4. I have a 20,000 gallon pool. When I opened it was green I have been running my sand filter 24/7 since I opened 2 weeks ago. The pool went from green to cloudy blue after a few days. Now I can’t get the cloudiness to go away. I have had the water tested at the pool store all chemicals are good. I have used a clarinet but nothing changes. The sand was replaced last year so that should not be the problem. From what I can tell the pool floor is clean of debris. Not sure what else it could be. Any suggestions?

      1. I am also having this same problem! Water is perfectly balanced and no longer green, but totally cloudy. I have a DE filter and started thinking I was blowing DE into the pool. I thought maybe some critters climbed in the open drain hole over winter and chewed up my grids. But the pressure does go up and I have had to backwash twice in the last week. But it is still not clearing up the water. Added clarifier a few days ago and nothing has changed.

        1. Hi Jen,

          Where you able to fix your issue? I am having the exact same issue and also thought D.E. was going into the pool. We are still struggling with the milky look, levels are great.

          Thanks in advance 😊

        2. The cloudiness could be dead algae that are still floating in the water. If you have to backwash that much, dead algae are what I suspect would be the problem. Use a flocculant, let it cycle through the water, then vacuum to waste

    1. In what key are you playing the clarinet? Kidding, of course. I presume you meant a clarifier.

      Usually, the cloudiness after an algae kill cycle is the remnants of dead algae. Try a flocculant or an enzyme cleaner like Pool First Aid to expedite the purge.

  5. Hello, I am having an issue with my pump/filter.
    Every time the pump is on, there is water coming out of back washing drain. even when its set on filter

  6. I have a cloudy pool. All of the ideas are possible, but my situation is a little different. My cartridge filter gauge never really goes up. I have a cloudy pool, but it never seems to climb. I swap the filter out after cleaning, but for the chemical clean you always say the pressure would go up. What would cause the pressure to never go up?? It has been a chore to get the pool going this year – trying to do it without emptying since I am on a community well. Any help would be great!!

    (I am battling with getting the ph down because the pool store told me to put 30 lbs of soda ash in it… ugh!)

  7. Some folks have told us to dump the ancient pool water and begin all over again with minimal chlorine granules.
    Others say to replace the sand filter with a D E filter and “all will be well and crystal clear”.

    I am beginning to hate this pool.

  8. Hi, opened pool over a month ago and still cloudy. Blue but cloudy, cannot are the button. Even did 2 floc treatments and never cleared up. We have a new cartridge filter, we had an earth filter but seemed to be blowing earth back into the pool so we bought a new cartridge filter and have a lot better pressure but not sure why pool won’t clear up! Thank you

  9. I have a well balanced pool in all levels, (Although Cyranic Acid is just at 30 – tested with test stips and pool store’s test machine,) but I still have white cloudiness 3 days after shocking. I ran my sand filter for 24 hours after shocking, vacuumed and then backwashed. I run my sand filter 12 hours at night. My filter is less than a year old and the gauge is operating correctly. I did add a 2nd dosage of clarifier 2 days after the 1st as I was not sure how old the first bottle was.

    Should I just keep things going as is and wait, or is there some thing else I should check.

    I had read on a different manual to do stain ban and Clarifier before shock. So I did that differently than I normally do for start up.

    Thank you

  10. Hello,

    Two questions. First, my pool water is hazy – can see the bottom but not distinctly. Changed the sand in my filter a couple of days ago as the previous owner did not leave records of maintenance. The internals looked good and the flow seems a little better. But, no improvement in the haze.

    The only chemical out of normal range is alkalinity at 180 ppm. Today, I added clarifier. I don’t mind allowing time for it to work, but about how long should it take for results?

    Also, can you provide the turnover data for a Hayward S244T filter?

    Thank you.

  11. Hi, I have a 12’ pool, added clarifier to it, then thought I’d flocc it as I had used channel water to fill,

    The flocc has worked a treat! But now I can’t get it out :$
    My filter does not do what needs to be done for vacuuming, I have been able to remove the bulk of it but there is a long way to go lol

    Will the clarifier have died with the flocc? Or will it be working in the background still?

    Apart from the fat chunks of yuck the water now looks great!

    1. Hello Gerhard – I will need a little clarification on some things. When you say the filter is not working, can you explain further? Has the flow slowed? Is there air in the system?

      When you began removing the floc debris, were you vacuuming to waste or straight into your filter? Most floc instruction state to vacuum to waste, as the floc globs can make the filter media unusable. For more information about the differences of these two, read our other blog: The Difference Between Pool Clarifier and Flocculant

      Clarifier works over a few days, whereas flocct in a few hours. The addition of the flocculant after the clarifier makes the the latter redundant.

  12. Hey Everyone! This is my first time on here “) We have had alot of rain this month and I have been on top of my water for the most part. I did take the water in to get tested the other day because although I know what I need in my pool to keep it balanced- I am not good t the math. I have a 12,000 gallon above ground pool with a sand filter. My water was clear and has been since we opened- never had a problem with algae or cloudy pool water. So here we go- Ph was low as well alkalinity and chlorine. My pool store is a mom and pop shop and they are great- not the kind to sell you products- I have been in many times and walked out not paying a dime. So I was told that I needed to add 12 pounds alkalinity (which is an amount I have never had to add before- and I had them test it twice because that seemed high to me) and was told to add 1 pound ph- let the filter run for four hours- then add 2 pounds shock (hypo-chlor granular- which is what we always use) and let pump run overnight. This morning my pool is cloudy. I can see the bottom but Its well–cloudy. I have never had this issue- even when I have had to add ph and alka before with shock. I backwashed the filter this morning- and tested the water- everything is on point in the normal range- chlorine reading are off the charts but thats to be expected after shocking. I am concerned about the cloudiness as my pool was crystal clear prior to adding the shock. I am hoping this will clear up- but seeing as how I have never had this issue is this a result of the shock? or a combination of all the chemicals? Even when I added to ph and alka the water was fine. My concern is how much alka is in there- even though it tested normal range this morning it seemed alot to have to add. Pool store is closed today so before I go and add any clarifier I want to make sure I am not adding something that will make it worse. Thanks.

  13. Cloudy pool

    I backwashed and oops forgot to rinse.
    I’ve added clear blue clarifier and will run filter overnight……..I’m assuming I will be able to vacuum and backwash / rinse a few times tomm….and hopefully problem solved.

  14. Can a pool become cloudy from stirring up soda ash? I work at a public pool and that morning they dumped in soda ash and it was cloudy the rest of the day, barely clearing up. It was clear the next day…

  15. I have a cartridge filter, and my water is more of an opaque than cloudy. Can only see maybe half foot down. I’ve tried balancing levels, and they are all good. Chlorine a little on the high side but not too much. The cloudiness won’t go away. we changed the cartridge filter no luck. I’ve also been vacuuming. I get quite a bit of leaves and particles out. some also rise to the top. I’m to the point where I want to use flock but don’t know how with a cartridge filter. Any ideas?

    1. Have you been dosing your pool with algaecide that contains copper?

      To use Floc with a cartridge filter, remove the cartridge from the tank while the Floc is circulating in the pool.

  16. Hi,

    We had an issue with metal in the pool that rusted and we were able to fully resolve it. Had sparkling water even! Shocked the pool and it was somewhat cloudy then 24 hours of filtration later it was perfect and sparkling again. We turned off the pump for 8 hours while at work (first time in 3 weeks it hasn’t been running) and came back to a pool that is milky colored. We have cleaned the filter and obviously have turned the pump back on and aren’t seeing any results. Suggestions??? We were so close!

      1. Hello
        My pool have clear perfect water but if any one go in water goes cloudly.
        If he go out agian its clear back.
        What is the reason of that

  17. Hello. I installed a FlowVis flow meter in my return line after my filter. I now have a cloudy pool and the filter is running at a higher pressure. Around 20 psi. Could the flow meter be restricting flow?

    1. Did the issue arise right after you installed the flow meter? Also, did you match the pipe size? meaning, if you have 2″ PVC, did you get a flowmeter that is piped with 2″ pvc?

      If your pool is cloudy, that could be dead algae. That could also explain the rise in filter pressure, dead algae clogs up filters quick. I would shock your pool, then run some clarifier, with a steady dose of backwashing or filter cleaning to clear it up.

      1. The clouding did occur after I installed it. It is sized to match the existing pvc. I installed it before I opened the pool. I have been shocking it about once per week. I have used algacide and have been chlorinating it. I don’t see algae on the walls and what i can see of the shallow end appears largely clean. Cant see the floor of the deep end. Its a 25000 gallon concrete pool with one filter intake and one return. I adjusted for ph and alkalinity this evening. How often do you recommend backwashing it?

        1. You don’t see algae because it is dead now. That cloudiness is the ghost of algae past.

          If you had algae when you opened your pool, then you shocked and killed it; the carcass of the algae bloom does not evaporate, it stays in your pool until you deal with it. You just need to keep filtering and backwash to get rid of it. Add clarifier.

          How to Clean a Green Pool?

          1. Thanks. I am beginning to see what you mean. I have been bringing the ph up and shocked it with liquid chlorine. Previous to that I vacuumed to waste and refilled the pool. I am back washing twice daily and getting results.

  18. We have a chlorinator for our pool. What type of chlorine tablets are the best? Or does it matter? I am looking at 2 systems: TrueBlue and Enjoy. Do you know or recommend either of these two?

    1. I am not familiar with either of those brands, but both should be able to do a decent job. Regarding chlorine tabs, I have heard big box store brands tend to be low quality.

      I would read the reviews, and then make your pick of the one you feel comfortable with. If it doesn’t do the job, move onto to a new brand; don’t think of it as being stuck with whichever brand you choose first.

  19. Hi my pool was green now its cloudy but small particles are still drifting on top of the pool how long before it clears up

  20. I have a cartridge unknown age but looks just fine. You touched upon this but so briefly not too clear.
    Back pressure did go up and it filtered fine – to a point. Now the fine stuff just passes through.

    My question is should I try replacing cartridge (expensive) or just buy clarifier (temporary).
    Is Home Depot filter as good as better name brand cartridge.

    1. The first step would be to buy a clarifier, it will gather up all those lingering particles. Then you can give your cartridge a chemical soak to clean it thoroughly; hopefully, that will fix any filtering issues. If the recycling dirt issue persists, I would change the cartridge because there could be a tear.


    1. I had the same issue.. come to find out that it was a cracked lateral in my filter and sand was going back into the wate. Hope this helps.

  22. Thanks for the information Charlie my pool now back to looking great, thanks to yourself for pointing out the fault’s that can happen. B-)

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