Rid Your Pool of Cloudy Water

 Cloudy pool water is caused by one of of the following — chlorine imbalance, pH or alkalinity imbalance, calcium hardness, ammonia, algae, a filtration problem, or outside debris — and in most cases it can be diagnosed and cleared up at home with a standard pool test kit. There's nothing worse than getting ready for a pool day and finding the water doesn't look right, so this guide walks through how to identify the type of cloudiness you're seeing, the seven most common pool water causes, and how to treat and prevent it going forward.

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 Pool Water? 

In total, there are seven major pool water causes behind a hazy pool. This might sound like a lot of things to investigate, but most of these problems 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 imbalanced pH levels won't be the immediate cause of your cloudy water, they affect other chemicals in the pool, leading to a chain reaction. Improper pH levels affect chlorine levels and calcium hardness, directly affecting your water's chemical balance and 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 in 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.

Ammonia

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 

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. 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 water 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!

Pool Water Treatment: Clearing Up Cloudy Water

Once you've identified the cause, pool water treatment and clarification generally follows the same order regardless of which of the seven causes you're dealing with:

1. Test first. Check free chlorine, pH, alkalinity, and calcium hardness before adding anything to your pool — treating the wrong imbalance can make cloudy water worse.
2. Balance the chemistry. Add shock, acid, alkali, or additional chlorine based on what your test results show.
3. Check your filtration system. Even a perfectly balanced pool will stay cloudy if the filter is clogged, damaged, or undersized for the debris load.
4. Keep up with skimming and pool maintenance. Regular skimming and post-storm testing prevent outside debris from overwhelming your filter in the first place.

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.

Frequently Asked Questions

What causes cloudy pool water? Cloudy pool water is usually caused by one of seven things: improper chlorine balance, pH and alkalinity imbalance, calcium hardness (scaling), ammonia buildup, early-stage algae, an ineffective filtration system, or outside debris.

How do I get rid of cloudy pool water? Start by testing your free chlorine, pH, alkalinity, and calcium hardness, then correct whichever is off with shock, acid, alkali, or additional chlorine. If the water stays cloudy after balancing the chemistry, check your filtration system next.

Can I fix cloudy pool water myself? In most cases, yes — testing and balancing your pool's chemistry can be done with an at-home test kit and the chemicals most pool owners keep on hand. Issues like calcium scaling or a damaged filtration system are trickier and are usually best handled by a professional.

Does AAA Pool Service help with cloudy pool water issues? Yes — AAA Pool Service is happy to help diagnose and fix cloudy pool water for Chicagoland inground pool owners, whether it's a chemical imbalance, algae, or a filtration problem.