Why Is My Pool Cloudy?

Having a backyard pool is a privilege, which makes it doubly hard to bear when you can’t go swimming in it because of unsightly cloudiness. It’s a question we hear every day at AOL Pool Shop: why is my pool cloudy?

Has your pool got that milky white look that doesn’t exactly entice you into its depths? This cloudiness can irritate your eyes and make for uncomfortable bathing.

So what’s the problem?

The Cause

If you have cloudy pool water, it’s probably either a chemical or mechanical problem. Either there’s something wrong with your pool water’s chemical balance, or there’s something wrong with a piece of pool equipment.


Cloudy pool water is often a sign your water chemistry is imbalanced. This could be the result of poor maintenance or of environmental factors such as not enough sunlight, too much heat or too much rain. Some of these problems could include:

  • Low chlorine levels
  • High or low pH levels
  • High total alkalinity
  • Early algae growth
  • High calcium hardness
  • Lots of tiny particles

If you haven’t got the right chemical balance in your pool, organic matter ends up deteriorating in the water, which leads to its cloudiness.


If you run a water test and everything comes up clean, there could be a problem with your filtration system.

Poor circulation

If your water can’t circulate properly, it won’t get an even distribution of chemicals. That allows organic matter to flourish and cloud the water. Blocked drains and skimmers and lower water levels can lead to poor circulation.

clear drains

Not enough filtration

Your pool filter should run 8 to 12 hours a day – any less and it won’t be effective. With poor filtration timing – or with a dirty and blocked filter – you simply won’t be able to combat an overgrowth of bacteria and algae.

The Solution

Thankfully, clearing up cloudy water is generally quite easy. You’ll typically find you have a chlorine or filter problem and can address the issue without too much fuss.

Step 1. Water Test

Before you take any drastic actions about combating your cloudy pool, you need to diagnose the problem. The only way you can do this is to test the pool water.

Pay special attention to pH, calcium hardness, and chlorine levels: if anything is out of whack, run the pool filter system for 12 to 24 hours before trying again.

Step 2. Diagnosis

If a chemical imbalance persists after you’ve run the filter system, you should readjust the appropriate chemical levels:

  • High pH or high total alkalinity: add a pH decreaser or pH reducer such as these Zodiac pH Down Tablets.
  • High calcium hardness: reduce the amount of calcium-based chlorine in your pool with a settling agent. If your calcium is really high, you might want to replace some of the pool water with fresh water.
  • Low chlorine: add a chlorine additive such as this Pool Chlorine Premium.

Check out our full range of pool balance products here.

If all chemical levels are in the normal range, your pool water has too much fine debris. You should backwash or clean the filter and run it for 24 to 48 hours straight.

Step 3. Clarify

If your pool water yields no clear results after balancing the chemical range or backwashing the filter, you may need to add clarifier.

Clarifier helps remove tiny particles by collecting them into larger particles. This increases the chances of your filter collecting them.

After you’ve added clarifier you need to filter the water continuously until it’s clear.

If you see no improvement, add a second dose.

Check out our full range of pool clarifiers here.

Step 4. Add Floc (Flocculant)

If all else fails, you may need to resort to a flocculant (such as these Power Clarifier Granules). Flocculant is a quick fix in case you need to use your pool in a hurry.

With flocculant you can clear your pool overnight – but there’s a bit of work involved. Pool flocculants send the fine debris to the bottom of your pool. But unlike clarifiers, they don’t help your filter collect the particles; you’ll have to do that yourself.

You’ll need to use a pool pump to manually suck that grungy murk right up out of your pool. An automatic pool cleaner will not work in this instance.

Make note: you don’t want the debris to go through your filter system, so set it to ‘waste’ or ‘backwash’ as you vacuum. But in sucking up that water, you’re going to lose pool water. Make sure you run fresh hose water back into your pool as you vacuum.

pool cleaning


Don’t forget that the best solution is prevention. There are some pretty neat tricks to keeping your pool crystal clear:

  • Have your water tested regularly
  • Filter for 8 hours every day/overnight
  • Check your water circulation regularly: make sure main drains and pool skimmers are open and inlet jets point down.
  • Vacuum and brush your pool regularly
  • Add pool water clarifier once a week
  • Make sure your filter is in good shape: check cartridge filters are in good condition.

Of course, sometimes it just isn’t easy to judge what’s gone wrong. If that’s the case, it’s best to speak with a professional. If you’re finding it difficult to diagnose and treat your cloudy water, call one of our swimming pool professionals on 1300 679 885.

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