How to Clear Cloudy Pool Water Fast (Step-By-Step Guide)

If the pool water is cloudy, this is often due to neglected water treatment. What should you do if your pool is cloudy, and how can you clear the cloudy pool water?

In order to clear cloudy pool water, the pool must first be scrubbed and vacuumed. Then the alkalinity, the pH level, and the calcium hardness are optimized to restore the water balance. Finally, a pool shock is done against the cloudiness in the pool.

In this article, you will find detailed step-by-step instructions against cloudiness in the pool and how to prevent this problem in the future.

1. Check the disinfectants in the pool

Before you start pouring any pool cleaner against cloudiness into your pool, the level of disinfectants needs to be checked.

The best way to do this is with an electronic water tester or simple test strips.

I purposely do not give a precise level ​​here, as there is a wide range of disinfectants for the pool.

Tip: In my blog article about pool chemicals, you will find a table with the ideal levels ​​for the different agents.

Let’s assume you use chlorine to disinfect the pool water, then you can use these charts ​​as a guide.

Chlorine Outdoor pool
Free chlorine 0.4 ppm
Combined chlorine 0.2 ppm
Total chlorine 0.3 – 1.5 ppm

The chlorine level in your swimming pool was probably too low, and the pool water tipped over.

We don’t optimize the chlorine level in this step. Move on to the next step.

Tip: If the chlorine level is high and the pool is still cloudy, there is probably too much cyanuric acid. This means that the disinfecting effect of the chlorine is lost.

I talked with a lady who let the pool pump run for 7 days without any noticeable success in clarifying the pool water.

This was because the cyanuric acid was at 106 ppm, but a 30 to 50 ppm level is recommended.

A partial water change is necessary in this case. Click on the link to read how to lower the cyanuric acid in the pool.

2. Test and establish the water balance in the pool

Test the water and, if necessary, optimize the alkalinity, the pH level, and the calcium hardness in your swimming pool.

The following parameters are considered ideal levels ​​in the pool:

Parameters Ideal level
Alkalinity 80 – 120 ppm
pH level 7.2 – 7.6
Calcium hardness 200 – 400 ppm

It is important that you first optimize the alkalinity in the pool.

Then the pH level and finally the calcium hardness in the pool are adjusted.

Whether your pH is too low or too high, you can find separate instructions in my blog.

If you need help, then click on the link to access the respective article.

Only then jump to the next step.

3. Shock the pool water

When the water balance – alkalinity, pH level, calcium hardness – is balanced, you have to do a pool shock (ideally in the late afternoon).

  1. Put on protective goggles and rubber gloves – alternatively, old clothes.
  2. Dosing of chlorine – 2 liters of liquid chlorine with a 150 g/l chlorine level for every 10 m³ of water. Alternatively, 4 liters of liquid chlorine with an 80 g/l chlorine level for every 10 m³ of water.
  3. The liquid chlorine is poured into the stream of the reflux nozzle.
  4. The pool pump must then run for 24 to 36 hours until the chlorine level falls below 1.5 ppm.

I strongly recommend using highly concentrated liquid chlorine for shock chlorination (also known as pool shock).

If you are performing a pool shock for the first time, I recommend the instructions linked to my blog.

It is important that the used chlorine for a pool shock is not stabilized.

The pool shock will not succeed with stabilized chlorine granulate because the effect is too slow and not intermittent.

Tip: If the pool is milky green, the pool water tends to tip over.

In this case, it is often enough to use a pool flocculant and let the filter system run through for 8 to 12 hours – provided the water balance is right.

If that is not enough, continue with the pool shock to remove the cloudiness in the pool water.

4. Use flocculants for better filtration of the pool water

After the highly concentrated chlorine has been poured into the pool, a flocculant is added to the pool water to improve filtration.

I always recommend using a flocculant when cleaning your swimming pool.

The flocculant increases the chances of success when cleaning cloudy water in a pool and, as already mentioned, improves the filtration with the sand filter system.

The best way to do this is to use flocculant pillows that can be placed in the skimmer.

5. Let the pool filter run

After using the chlorine in combination with the flocculant in your pool, it is time to start the pool pump.

Let the filter system run through for 24 to 36 hours until the pool becomes clear again and the chlorine level has dropped below 1.5 ppm.

It is not allowed to stay in the swimming pool beforehand.

Meanwhile, the pool is scrubbed with a pool brush to get rid of deposits caused by algae – 2 to 3 times within 24 hours should be sufficient.

Scrubbing loosens remaining deposits and boosts water filtration.

Tip: In the case of particularly persistent cloudiness in the pool, it can be helpful to scrub the pool with a brush before the pool shock and then vacuum the floor with a pool vacuum. Alternatively, use a pool robot.

6. One final water test

The cloudy pool water should now be clear again.

Finally, the water parameters ​​are tested again and, if necessary, optimized – see table above.

I also recommend using the algaecide in your pool to inhibit algae growth.

It’s best to buy a foam-free algicide.

Info: You may only take a bath again when the chlorine level in your pool has fallen below 1.5 ppm – the level will decrease due to the filtration.

If you’ve dumped too much chlorine into the swimming pool, you can use a chlorine neutralizer.

Causes why the water in the pool is cloudy

I explained how to get rid of cloudy pool water, and I can imagine that it was not easy for you.

So that this doesn’t happen to you again, you should know the exact reasons why the swimming pool gets cloudy in the first place.

1. Heavy metals lead to cloudiness in swimming pools

The pool water becomes cloudy when too many heavy metals are in the water.

This can be copper or iron, among others.

If there is a metal-related problem in the pool water, this can be recognized by a brown-black to light green color cast.

But how do the metal deposits get into the pool water?

  • An overdose of di-chlorine and tri-chlorine.
  • Iron and copper end up in the basin when filled with well water.
  • The pH in the water is too low and can rust metal parts in the pool.
  • You use a bad algaecide with a high copper level and overuse it.

It is not a problem to fill the pool with well water if you clean it with a long filtration and suitable pool cleaners.

In most cases, chlorine is enough, but sometimes a remedy for iron and copper in the pool is also required.

Many beginners use a phosphate remover in addition to metal removers, which negates each other and leads to further complications.

You will learn the full truth about phosphate in the pool in my post.

The worst thing you can do with a metal-related problem is to try and use vitamin C to get rid of the cloudy pool water.

Vitamin C only has a cosmetic effect, and the deposits are not removed.

Later the pool water gets even dirtier and requires more effort to clean the pool – in my blog, you can find more information on the use of vitamin C in the pool.

Take the problem of low pH and metal build-up in your pool seriously. Sloppy pool care can result in costly damage to the pool frame and equipment.

2. The dosage of disinfectant in the pool is bad

Inefficient use and the poor dosage of chlorine, bromine, etc., is one of the main reasons why the pool water becomes cloudy.

  • The ratio of free chlorine to water volume is incorrect, and the proportion of organic particles increases.
  • The chlorine is dosed above the ideal level of 1.5 ppm.
  • Missing cyanuric acid when using non-stabilized chlorine.

Bad pool care does not only happen if you use too little disinfectants in your pool.

A combination of different pool chemicals can also reduce the disinfecting effect in the pool.

For example, you cannot use chlorine with biguanide or active oxygen.

3. Cloudy pool water due to a problem with algae

Algae in the pool are a clear sign of a lack of disinfectant in the pool.

In the worst case, the algae can turn the pool water overnight into a green monster – the green color comes from the green algae.

The first signs can often be seen in the form of a slight white coloration in the pool water.

If you don’t take action against the algae in your pool, the pool water will turn green after a few hours.

Therefore – as already recommended – quick actions are required.

To be able to react quickly to the milky color of the pool water, you should always have the right pool chemicals in stock and not only go shopping in an emergency.

A non-foaming algaecide can help to temporarily inhibit the growth of algae.

Weekly, 1 liter/100 m³ of pool water is good. With a 50 m³ pool, this is 0.5 liters per week.

I will explain how to clear milky pool water in a separate article. Simply click on the link to read my instructions.

4. Short filter run times in the pool

There is no point in using pool chemicals to maintain the water balance and at the same time trying to save electricity by reducing the pool pump running times.

The pool water must run through the filter system in your pool at least once a day within 6 – 8 hours.

On particularly warm days in summer, an extended filter run time is even necessary.

If you don’t do that, do you know what happens then?

Yes. The pool water becomes cloudy.

In my blog post, you can check the runtime of the pool pump and read more about the filter runtimes.

How to prevent cloudy pool water in the future

Cleaning cloudy pool water is no fun!

It only costs extra time and money for general pool maintenance.

However, this can easily be prevented by following the following tips against cloudy pool water.

  • Optimize the filter runtimes: Is your pool pump the right one concerning the size of your swimming pool, and are the filter runtimes observed? Ideally, the water should be completely filtered once within 6 to 8 hours/day.
  • Test pool water regularly: Take an electronic water tester and check the parameters (pH level, alkalinity, chlorine level, calcium hardness,…) in the pool water at least 1 to 2 times a week. Daily measurement is recommended when you use your pool frequently and the days get hot.
  • Use a skimmer and pool net: With the skimmer and a suitable pool net, dirt is removed from the water’s surface. Reducing the organic materials in the pool helps to prevent cloudy pool water.
  • Sucking up dirt from the floor: If dirt lands on the pool floor, it should be vacuumed with a pool vacuum. For practical reasons, I recommend the battery pool vacuum.
  • Use a flocculant: Make sure that there is a flocculant pad in the skimmer every 2 weeks to improve the water filtration in your pool. Liquid flocculants work too, but white flakes can form on the bottom due to the concentration.
  • Use a footbath: Place the footbath in front of your swimming pool to minimize the dirt. You will be amazed how long the pool water stays clean with this simple gadget.
  • Bathing rules: Make it that every swimmer has to shower before entering the pool. This reduces the number of colloidal particles in the water and prevents cloudy pool water.

Do you have any further questions about how to clear cloudy pool water?

Contact me at @contactswimfool on Twitter, Facebook, Pinterest, and other popular social media – I’ll be happy to help you personally.

Have fun cleaning cloudy pool water!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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