Rid Your Pool of Cloudy Water

Rid Your Pool of Cloudy Water

There's nothing worse than getting ready for a pool day and coming out to see the water doesn't look normal. 

Don't worry – a cloudy pool isn't the end of the world. Murky water happens for a variety of reasons. But often, it can be corrected with tools you already have at home. Let's take a closer look at the different reasons for cloudy pools and ways to clear up your water. 

Types of Pool Water

Before we jump in, so to speak, let's first tackle the type of cloudy water you have in your pool. The type of cloudiness will help you (or your pool professionals) assess the severity of the problem and, potentially, the cause.  

When looking at your pool, does it look…

  • Dull or Flat? This is the least concerning type of "cloudy" pool. It means that you can still see the bottom of the pool, but there is a noticeable lack of "sparkle" in your water. 
  • Hazy? Once again, you can still see the bottom of the pool, but now it's hard to make out floor details, such as tiles or texturing. 
  • Milky? Your water is undoubtedly cloudy or "milky" and it's no longer translucent. Now, you can't see the bottom of your pool at all. 

Now that you've established the type of cloudiness you're experiencing, we can move on to finding out the reason why. 

What Causes Cloudy Pools? 

In total, there are six major reasons why your pool could be going hazy. This might sound like a lot of things to investigate, but most of these problems all revolve around your pool's chemical balance. Let's start there. 

Improper Chlorine Balance

Of course, you know that your inground pool needs chlorine to stay clean and healthy. But sometimes, it's easy to fall behind on consistently adding the right amounts of chlorine all summer. 

If your pool is cloudy, it could be because your free chlorine levels are too low.

Free chlorine refers to the amount of "clean" chlorine available to fight and kill off bacteria in your pool. Combined chlorine is already attached to these germs, so it can't fight off others. Think of chlorine like a bee. Free chlorine still has a stinger and can defend itself. Once a bee stings something, it's unable to do so again, just like combined chlorine. 

With low free chlorine levels, there's not enough chlorine to attack new germs and bacteria. Then the pool gets overwhelmed with combined, contaminated chlorine, causing cloudy water. 

Test your chlorine levels – ideally, they should be between 1 and 3 parts per million (ppm). If it's below or above these levels, it's time to add shock to your pool. 

pH and Alkalinity Imbalance 

Check your pool's pH and alkalinity levels if you don't have a chlorine imbalance. 

Like we learned in biology, the pH scale measures how acidic or alkaline a substance is. In this case, your pH level measures how alkaline your pool water is. On the pH scale of 1-14, the ideal pool alkalinity is between 7.4 – 7.6. If it's any lower (too acidic), it can easily irritate your swimmers' skin and eyes. It can also eat away at your pool surface. Any higher (too alkaline), you're at risk of a buildup of germs and bacteria. 

While the pH levels being imbalanced won't be the immediate cause of your cloudy water, it affects other chemicals in the pool, leading to a chain reaction. Improper pH levels affect chlorine levels and calcium hardness, directly affecting your water's health. 

If you test your water and find a pH imbalance, you can add acids or alkalis to your water to restore it. A balanced pH level will help clear up other issues and your pool as well. 

Calcium Hardness

If those two don't seem to be the culprit, let's check the calcium levels in your pool. 

You're finding out how much calcium is in your pool by checking your calcium hardness levels. Just like with chlorine and alkalinity, having too little or too much calcium can have adverse effects on your pool. With too little calcium, your pool foundation and walls could be damaged. But it's too much calcium that can lead to cloudy water. 

Finding high levels of calcium hardness in your water means you have too much calcium, which inevitably leads to "scaling." Calcium scaling is when white and grey stains appear on your pool's walls. If you start seeing this scaling, take action - it builds up and can be tough to remove. You can tackle it with a pumice stone if you're doing it yourself. But we recommend talking to a professional pool cleaning service to find the best solution. 

Calcium scaling is what causes cloudy water when you have high calcium hardness levels. Fixing that may require more steps than simply adding shock or additional chemicals. For more information about restoring your calcium hardness levels, learn more here.


Your cloudy water could also be a sign of the presence of ammonia in your pool. 

If a pool isn't properly maintained, bacteria and germs will build up, leading to ammonia. Ammonia is a water contaminant brought in by humans or other debris. If you see high chlorine demand, low free chlorine levels, low cyanuric acid levels or high chloramine (combined chlorine) levels, these are signs that there is too much ammonia in your pool. 

The best way to combat an excess of ammonia in your pool is to add a good amount of chlorine. You want to use enough to reach high free chlorine shock levels, between 5 – 10ppm. When it comes to a type of chlorine, liquid chlorine will be the quickest way to combat this issue and won't affect the other chemical levels in your pool. 

(To fix your cyanuric levels, you'll also have to add additional cyanuric acid once you've removed the ammonia from your pool.)


Algae in your pool can cause all types of problems, including cloudy water. Specifically, though, the early stages of algae can cause cloudy water.  

The presence of algae is also connected to your chlorine levels, which you should test immediately when you see cloudy pool water. 

To test if algae is starting to form in your water, you can perform an overnight chlorine loss test. To do this, check your free chlorine levels and add chlorine after the sun goes down. This way, the sun won't deplete the levels of added free chlorine in your pool overnight. Test your water again the following day and compare it to last night's numbers. If your free chlorine levels dropped by 1ppm overnight, you almost certainly have early stages of algae building in your pool. 

If adding shock to fix your chlorine levels does not solve your algae issues, removing an algae infestation may require sanitation and additional pool shock treatment (this article from SwimUniversity has excellent tips on this). If you need professional help removing your algae, we're happy to help!) 

Ineffective Filtration Systems

A cloudy pool means you should also check that your filtration system is working correctly. A cloudy pool is inevitable if it's clogged or your cartridges are worn out or broken altogether. 

Your pool filter could also be experiencing a buildup of debris or sand, too much or too little pressure coming from your tank, or damaged gaskets, grids and baskets. 

If you're unsure if your pool filter is working properly, reach out to a pool professional for help. They'll be able to assess your situation and recommend the best products for your pool. 

Outside Debris 

Have you been skipping on skimming your pool lately? Have bad summer storms filled your pool up with unwanted debris? Twigs, sticks, leaves, flowers dirt and sand can easily cause your pool to cloud. This is because they can build up in your filter, which leads to it being less effective and less able to keep your water clean and sparkling. 

Instead of letting your filter do all the work, make sure you're helping by skimming your pool as needed.  

Also, storm runoff water can add nitrates, phosphates or sulfates to your pool, changing the chemical balance. Be sure to test your water if your pool remains uncovered during a big storm!

Steer Clear of Cloudy Pools

We hope these tips help you navigate clearing up your pool's cloudy water. As we said, many of these can be completed on your own, with tools and chemicals you have on hand. 

But if you're feeling overwhelmed by fixing your cloudy pool yourself, call a pool expert. AAA Pool Service is happy to help you tackle your hazy pool and get you swimming again as soon as possible.