How to Clear Cloudy Pool Water

Written by Michael Dean
December 14, 2023

water clarifier next to a cloudy swimming pool

It can be quite a disappointment to go out for a swim, only to notice that your pool has lost its sparkle and is a cloudy mess. A cloudy pool indicates something has gone wrong or that there may be more serious threats at play.

In this article, I will cover the reasons for cloudy pool water, my process for how to clear it, and answer the most common questions I constantly hear about cloudy pools.

Main Takeaways

  • Some reasons for cloudy pool water include: low chlorine levels, contaminants, unbalanced water chemistry, and bad filtration.
  • To clear cloudy pool water, you must shock the water, filter and vacuum debris, balance your pool chemistry, and then use a clarifier or flocculant.
  • Cloudy pool water should clear within 2-3 days.

Reasons for Cloudy Pool Water

Chlorine is an essential tool for ridding your pool of contamination, but it should not be your ride or die. You will need to have a treatment strategy beyond chlorine and a method of clearing your pool of exterior contaminants. Ultimately, cloudy pool water boils down to culprits in one of these categories.

Low Chlorine Levels

For your pool to have clear water, it needs to have the right chemical balance. Balanced pool water is more attractive and safer for those wanting to swim in it. Free chlorine is the amount of unused chlorine still available in the pool. When free chlorine is low, chloramine is produced.

The presence of chloramine from low chlorine levels not only turns the water cloudy, but it also isn’t as effective at killing off germs and bacteria. A pool with low chlorine levels needs to be shocked immediately to prevent ammonia or algae from forming.

How to Fix It

  • Check your chlorine levels more often and make sure the optimal amount of free chlorine and combined chlorine is in the water. Free chlorine should stay between 1 to 3 parts per million, while combined chlorine should rest around .5 parts per million.
  • The sun will break down chlorine over time, so this is why cyanuric acid is important to slow this process down. Check the cyanuric acid levels and add more of the chemical if necessary.
Taylor High Range Swimming Pool Test Kit

This expansive test kit includes nine tests for most pool chemical measurements you need.

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Outside contaminants such as pollen, debris, and leaves are another cause of cloudy pool water. It is common for these to enter the pool during rainy or windy days. When debris enters the pool, algae may begin growing in the water, which often causes cloudiness. During a rainstorm, the excess water will also lessen the effects of chlorine because it will dilute the water.

How to Fix It

  • If you notice algae is growing, shock the water. Use a brush to aggravate the algae on the edges of the pool (where algae will generally grow), and use a pool vacuum to remove it.
  • Test your chlorine and pH levels and add more chemicals where necessary.

Unbalanced Water Chemistry

There are a few chemicals that you will put into the pool to balance the pH level. Water pH falls on a scale of 1-14, but the optimal reading is 7.4 (the same in human eyes and membranes). Pool water with pH levels higher than 7 is basic, while anything lower than 7 is acidic. Unbalanced alkalinity and calcium hardness are also common causes of cloudy pool water. Check out my guide on swimming pool water chemistry to learn how to use the correct levels of all those chemicals. Phosphate removers can also cause cloudy pool water.

How to Fix It

  • Frequently test your calcium hardness and pH levels, and add more chemicals to balance when needed.

Bad Filtration

Your swimming pool filter helps siphon contaminants like leaves and insects out of the pool, and helps circulate the water and keep it from being stagnant. Stagnant water can cause cloudiness and a greasy film to form.

Contaminants can include microbes and even human waste. The presence of human fecal matter in the pool can potentially expose swimmers to E.coli, so water must circulate adequately.

How to Fix It

  • Clean your pool filter regularly and change your filter cartridges at least bi-annually. If your filter seems to be causing your water to be cloudy often, then it is likely time to get a larger pump.
  • Your skimmer basket may be overflowing with leaves, sticks, and dirt, spitting it all back into the water. Check the basket and remove any debris.
  • As a general rule of thumb, you should be running your pool filter for longer than 8 hours per day. If your filtration is failing, you may want to increase the time your filter is on every day.

Step-by-Step Process: How to Clear Cloudy Pool Water

Here is my four-step process to clear up cloudy water. If you have a saltwater pool, head to my research on clearing up a cloudy saltwater pool.

Step 1: Shock The Pool Water

When you raise the chlorine levels to get rid of unwanted contaminants, you are shocking the pool. Pool owners will shock their pool to destroy bacteria, algae, and other organic materials. To kill algae, some recommend double or even triple “shocking.”

You don’t add chlorine directly, but use a pool shock like:

Next, calculate the amount of water in your pool and calculate the pool shock volume, which should be 1 pound for 10,000 gallons of water. Check the instructions of the product you purchase for more specific guidelines.

In The Swim Calcium Hypochlorite Chlorine Granular Pool Shock

In The Swim has a reliable cal hypo shock that is effective and easy to use.

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Step 2: Filter and Vacuum Debris

Determine whether the pool filter is running correctly. I recommend that you run it for at least 8 hours per day. If you keep the pool clean and chemically balanced, 8 hours should be enough filtration time to keep the average backyard pool clear and fresh.

Your skimmer will take care of any debris floating on the surface, but to thoroughly clean the bottom of the pool, you will need a pool vacuum.

Step 3: Balance Your Pool Chemicals

Once the water is thoroughly clean, test the alkaline, pH, and chlorine levels in your pool using a test kit. You can buy them online or take a sample to the local pool store for analysis.

Adjust chemicals like muriatic acid and use a chlorine stabilizer to maintain your current chlorine levels. Here is a guide for some of the recommended chemical balances in your swimming pool:

Step 4, Option 1: Use a Pool Clarifier To Clear Cloudy Pool Water

Using a pool clarifier will help eliminate all the smaller particles that the filter cannot remove. Pool clarifiers gather the tiny particles that pollute the water and bring them together to make larger clumps that a filter can easily pick up. Pool filters cannot always pick up the smallest bits, so clotting them together makes cleaning up easier. When pouring in the pool clarifier, keep the filter running and ensure that your pH levels are good to go.

Clorox Pool&Spa Super Water Clarifier

Clorox makes a good clarifier that I recommend for most pool owners trying to solve a cloudy pool problem.

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Step 4, Option 2: Use a Flocculant To Clear Cloudy Pool Water

Using flocculant is another even quicker way to clear up the water. Flocculant works similarly to clarifier. But instead of the particles gathering into small clumps and staying at the top of the pool, they will form much larger clumps that will sink.

BioGuard Powerfloc

This solution from BioGuard is really effective and is what I use when I need a powerful flocculant.

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Still not sure on the difference between the two? Read my complete guide on pool clarifier vs. flocculant.

Step 5 (If You Use Flocculant): Vacuum Up the Remaining Particles

Although using flocculant does save time overall, it requires more manual work. Because the particle clumps from the flocculant are too large for the filter to remove, you will need to use a manual vacuum to remove the debris. Automatic pool cleaners will not remove the debris. Too much vigorous movement will cause the clumps to separate and can make the water cloudy again. So make sure to be gentle with your vacuuming.

Here’s a good video that goes over the steps I mentioned above.

Get My Free Pool Care Checklist

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Frequently Asked Questions

How Long Should It Take to Clear a Cloudy Pool?

Without knowing the cause of the cloudiness, it isn’t easy to give a specific answer on how fast it will clear up. For most of the issues we have mentioned, it shouldn’t take more than 2-3 days before water appears back to normal.

Flocculant will only need about 8-16 hours to work its way through the water, gathering large clumps of debris. On the other hand, clarifier takes 2-3 days to run its cycle. Shocking is a 24-hour process, and if poor filtration is the culprit, you will still need to allow the filter to run for 12 hours after cleaning it up.

Can I Swim in a Cloudy Pool?

I recommend identifying the cause of cloudy pool water before taking a dip. If the water is dirty because the filter is not getting rid of all the debris, it’s technically safe to swim in. But it’s not recommended as the filter isn’t circulating water to remove bacteria.

Cloudy pool water is also a sign of a chemical imbalance. Basic water doesn’t kill all bacteria, and acidic water is very irritating to the eyes and skin.

Why Is My Pool Water Still Cloudy After Shocking?

The process of shocking your pool requires about 24 hours, so don’t expect immediate results. You also want to make sure to use a shock that has an active ingredient of calcium hypochlorite. Big-box stores will often provide a less expensive product that does not contain calcium hypochlorite, but avoid this as it is less effective.

If the pool hasn’t cleared up in a couple of days after applying shock, it’s likely a water circulation issue. If this is the case, clean your filter and make sure it is cycling correctly.

Will Baking Soda Help Clear My Cloudy Pool?

You can use baking soda for quick cosmetic fixes, like scrubbing algae or grime, but it shouldn’t be a long-term solution. Because baking soda is basic, it will increase the pH level of the water, making it cloudier. Read my article on how to use baking soda in your pool for good use cases.

Will Bleach Clear a Cloudy Pool?

Bleach can help clear a cloudy pool…only to a certain extent. Bleach is sodium hypochlorite, which helps kill bacteria that can cause cloudiness. Is it as effective as other methods? No. Can you use it? Yes.

Will Heavy Rain Make My Pool Water Cloudy?

Thunderstorms will bring all sorts of problems to your swimming pool. Heavy wind and rain can wash dirt, branches, and leaves into your pool, causing algae growth and making the water cloudy. Heavy rainfall can also deplete the chlorine in your water, which will encourage microbes to grow. Head over to my articles on what to do to your pool after it rains and how to clear cloudy pool water after a rainstorm for more information.

Will Cloudy Pool Water Clear Up On Its Own?

If cloudy pool water is left unattended for some time, it will get much worse. Cloudy pool water generally means there is a chemical imbalance or algae growth, so it should be shocked and cleaned. After shocking, the cloudy water may clear up in a few hours, but it may still need more attention.

Final Tips on Keeping Your Pool Water Clear for Good

To keep your pool looking flawless all year round, remember these tips:

  • Routinely deep cleaning will help prevent the water from getting cloudy and keep it from losing its “sparkle”.
  • You can also keep the water looking fresh by stirring it and skimming a few times a week for debris or manually using a pool brush to push the particles down towards the filter.
  • Regularly shocking your pool and backwashing the filter will go a long way in preventing cloudiness.
  • You can also anticipate cloudiness by taking a pressure gauge reading and backwashing whenever the pressure reaches 5-7 pounds per square inch above average readings.

Remember, treat your pool like an art project. Clean the area regularly and make yourself aware of the common threats that change the water’s properties.

Keep up with hygiene codes for family and friends, and keep tabs on your equipment for constant monitoring and maintenance. If you take the time to keep your pool looking beautiful, it will look as clear as glass for the summer months!

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