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How to Clear Cloudy Pool Water

If you’re new to pool ownership, it’s almost inevitable you’ll encounter the issue of cloudy or turbid water at some point.

By the end of today, though, you’ll know how to clear cloudy pool water, and you’ll also have an understanding of why your water becomes contaminated in the first place.

The good news is, clearing cloudy pool water couldn’t be much easier. Although it requires getting to grips with some basic science, we’ll strip that back into plain English for you in today’s guide.

I. 5 Most Common Reasons for Turbid Pool Water


To discover how to clear cloudy swimming pool water, it pays to know why water gets like this in the first place.

Here are the most common reasons for turbid pool water:

  1. Chlorine levels are too concentrated or too diluted
  2. There’s too much calcium in your pool water
  3. You have problems with your pool filtration system
  4. pH levels are too high or too low
  5. There has been a heavy rainstorm

1) Chlorine levels are too concentrated or too diluted

You need to add chlorine to your pool water to keep it safe for swimming. Chlorine kills bacteria and microorganisms capable of causing health conditions like athlete’s foot, ear infections, and even Legionnaire’s disease.

The chlorine levels in your pool will ebb and flow depending on how many people are using your pool, the amount of rain falling, and the amount of sunlight penetrating the water.

The greater the difference between free chlorine and total chlorine, the more chloramine (combined chlorine) is present in the pool water.

Combined chlorine levels should always be below 0.5 parts per million (ppm), or even 0 ppm if practical.

Test your chlorine levels daily and make adjustments as required.

2) There’s too much calcium in your pool water

The hardness of your pool water can impact whether it’s clear as glass or murky and cloudy.

If calcium levels are high and the water is hard, it’s more likely to be turbid than softer pool water.

Beyond this, when calcium levels in your pool are too high, this can damage both the plumbing and your pool filter. If the water is too soft, on the other hand, pool surfaces can more easily wear down, reducing the lifespan of your above-ground pool.

3) You have problems with your pool filtration system

Your pool pump and filter need to be running for a certain time each day to keep your pool health strong.

How long you need to run your filter and pump depends on how big your pool is, how often it’s used, and the type of filter (cartridge filter or DE filter).

As a guideline, running the filter for 8 hours daily is optimum.

Failing to run the filter for long enough can cause the pool water to stagnate. As debris and microscopic particles accumulate, so the pool water becomes opaque and turbid.

4) pH levels are too high or too low

The pH levels in your pool express how acidic or basic the water is.

If the water is basic with a pH level of 8.0 and above, the chlorine is unable to work efficiently. When the water in the pool is too acidic (pH level of less than 7.0), this can cause damage to the pool lining. As the lining corrodes, this can cause debris to make the pool water appear cloudy.

5) There has been a heavy rainstorm

Excessive amounts of rainwater can interfere with your pool’s chlorine levels.

We understand it’s not always possible to use a pool cover every time the heavens open, so make sure you check up on your pool after a heavy storm. If the water seems cloudy, test the pH levels and chlorine levels with a pool testing kit.

II. When Was the Last Time You Shocked Your Pool Water?

In some cases, shocking your pool is the best way to address issues with the water.

Any time you notice a strong smell of chlorine, or any time the combined chlorine levels are too high, you should consider using some pool shock ASAP.

When you shock your pool water, this raises chlorine levels to 10 ppm. This ultra-high dose breaks down the chloramine responsible for that trademark smell. At the same time, this process kills pool algae and bacteria that can lead to green pool water.

Unfortunately, cloudy pool water is often a by-product of shocking.

So, how can you rectify this issue?

III. How to Clear Cloudy Pool Water in 6 Easy Steps

Here’s all you need to do to fix cloudy swimming pool water like a pro:

  1. Test your pool water
  2. Use pool clarifier
  3. Use pool flocculent
  4. Give your filtration system some assistance
  5. Replace the pool filter if necessary
  6. Stay on top of routine maintenance

1) Test your pool water


You might be able to see at a glance that your pool water is not crystal clear, but you’ll need a pool testing kit to dial in the root cause.

The best pool testing kit lets you measure a number of variables capable of impacting the quality of your pool water. This helps you to more easily recalibrate the levels.

Test strips will measure:

  • Chlorine
  • pH
  • Calcium hardness
  • Total alkalinity

High calcium hardness, high pH levels, and high alkalinity can all trigger cloudy pool water.

Other types of pool testing kit contain reagents. You add these reagents to your pool water and they turn a variety of colors depending on how much chlorine is present, and also on the pH levels.

Whichever method you employ, it’s vital to source your pool water the right way. Ideally, grab a sample from 18 inches below the surface. Get the water sample first thing in the morning before the sun has the opportunity to burn off any chlorine.

Sometimes, simply adjusting these levels is enough to correct cloudy pool water.

When pool water is too acidic, add some sodium carbonate and you’ll raise pH levels. If the pool water is too basic, pop in some sodium hydrogen sulfate or hydrochloric acid and you’ll lower pH levels.

You should always use cyanuric acid to protect and stabilize your chlorine levels.

2) Use pool clarifier

Prevention is often better than cure, so you might use using a pool clarifier restores some brilliance to your pool water.

When you introduce pool clarifier to the water, it causes microscopic particles in the water to clump together so your pool filter can more readily process the particles and eliminate them from the water.

3) Use pool flocculent

Pool flocculent, often abbreviated to pool floc, operates similarly to pool clarifier, but the two are not exactly alike.

If you use pool floc, you simply dissolve the powder in some water before applying it over the surface of your pool water.

You need to switch off your pool filter pump and then wait for up to 48 hours before you notice the effects.

As you wait for the pool floc to kick in, the particles will start binding together. Rather than passing through the pool filter, they’ll gather on the pool bottom. Get rid of the accumulated debris by using a manual pool vacuum to suck up the particles.

4) Give your filtration system some assistance

Your pool filter is typically situated at the top of your swimming pool. While this helps to remove particles floating to the top efficiently, it doesn’t work so well when debris gets captured on the bottom.

You have several options for improving the efficiency of your pool filtration system. By taking these steps, you should improve the clarity of the pool water.

  • Draining the water: If you have an in-ground swimming pool, you will likely have at least one drain on the bottom. If you occasionally open this up, this will boost the circulation of the pool water so the particles rise from the bottom to the top of the pool. Here, the filter will clear them out efficiently
  • Vacuuming the pool: If you have an above-ground swimming pool and no drains to take advantage of, you can replicate these effects by using your pool vacuum. Place the pool vac on the bottom of the pool in the center and turn it upside down. This will agitate the particles and channel them upwards into the filter
  • Stirring the water: If you use a pool brush, you can help remove some debris from the bottom and push it up toward the surface

5) Replace the pool filter if necessary

If you ensure your pool filter is always clean, it will work more efficiently, and it will also improve the overall performance of your pool.

As more debris and more particles accumulate in the pool water, so it needs to work harder to compensate.

Over time, a neglected filter can become clogged to the extent it won’t do anything to clear the pool water.

At least twice during each swimming season, use a commercial filter cleaner for best results.

If you determine that the filter is too clogged up, it might be most expedient to buy a replacement.

6) Stay on top of routine maintenance

If you keep on top of maintaining your swimming pool little and often, this will not only keep the water looking crystal clear and inviting, but you’ll also remain confident that everyone who swims in your pool can do so safely.

Try creating a weekly maintenance schedule so you can take care of the quality and health of your pool without becoming overwhelmed.

Consider the following weekly tasks:

  • Remove all larger debris like leaves from the pool water
  • Run your pool vacuum
  • Brush the bottom and the sides of your pool. This will remove dirt and algae
  • Test the chlorine and pH levels of your pool
  • Check other levels in your pool water as required
  • Use pool shock
  • Check the filter

IV. Could Your Cloudy Pool Water Be Due to Algae Growth?

Sometimes, pool water can be extremely cloudy and resistant to clearing up. This doesn’t happen often, but when it does, it’s typically during the beginning of summer when swimming pools are opening after being closed over winter.

Maybe you notice the following markers:

  • Cyanuric acid levels and FC levels drop to zero or close to zero
  • CC levels are very high
  • There is a high demand for chlorine in the pool water
  • FC levels still won’t rise easily, even if you add lots of chlorine

This suggests you could have ammonia in your pool. You’ll need to use of chlorine to combat this.

The early stages of algae growing can often lead to the pool water appearing dull and cloudy. How you can determine whether this is blighting your pool, though?

Well, add some chlorine to your pool water during the evening. This will avoid reducing FC levels as the sun will be down. Then, administer an OCLT (overnight chlorine loss test and take FC readings the following day.

If you discover that FC levels have dropped by more than 1 ppm overnight, you have algae starting up in your pool.

Both ammonia and algae, then, arise when FC levels in your pool are too low, so stay on top of this to avoid disappointingly turbid water.

V. Conclusion

We hope today’s advice on how to clear cloudy pool water has left you perfectly placed to restore your contaminated pool to its former glory.

As long as you keep abreast of proper pool maintenance, you should hopefully avoid this issue in the first place.

Take a moment to bookmark our blog before you head off. We are undergoing a period of expansion here at Wild River Country and we’ll be bringing you more great guides in different areas of outdoor life. Watch this space and come back soon!

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