How To Fix Cloudy Pool Water

When your pool water becomes cloudy (sometimes overnight!), it can be a difficult and time-consuming process to return it to its ideal clear state. By learning what causes the water to become cloudy and familiarising yourself with a few maintenance methods, you’ll learn how to fix cloudy pool water in no time at all!

Why Do I Have Cloudy Pool Water?

There are many reasons why you may have cloudy pool water. We’ve broken it down into three main causes:

1. The Pool Filter

Your pool filter system constantly cleans the water in your pool. Without it, you’re left with stagnant water that could become cloudy. Nine times out of ten, pool clarity issues are linked to filtration. If you have a cloudy pool, something may be wrong with either your sand or cartridge filter.

2. The Environment

Everything that surrounds your pool can cause your water to become cloudy. These environmental factors can include the weather, birds, construction work, trees and plants, the sun, people, and pool algae.

3. Pool Chemicals

Excessive levels of pool chemicals can cause your water to become cloudy. High pH, high alkalinity, high chlorine or other sanitisers, and high calcium hardness are all common culprits. Often, running your filter as per usual should help even these levels out over time, but if you do have an imbalance, we'd recommend testing your water and fixing it.

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How To Clear A Cloudy Pool

Once you have investigated all the possible problems that could be causing your pool water to become cloudy, it’s time to find a cloudy pool water solution. Here are three ways to clear your cloudy swimming pool.

1. Check Your Filter

Here is a quick checklist of questions thata you have to ask yourself if you have a cartridge filter:

When was the last time you cleaned your cartridge?

If it’s been a while since you last cleaned your cartridge, take it out and give it a good hose down. If you are after a thorough clean, soak your cartridge in a tub of clean water with some of our Zodiac Filter cleaner for at least 12 hours. After that, give it a good rinse and it should be as good as new!

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Have you recently added any flocculants or clarifiers to your pool?

As your cartridge filter is made from layers of paper, flocculants and clarifiers will clog your cartridge and should be avoided at all costs. You can use them if it's an emergency, but be prepared to replace your cartridge filter element(s) when you're done.

How old are your cartridge filter element(s)?

Depending on what chemicals pass through them, your pool usage, and how often they are cleaned and maintained, cartridge filters have an average life span of anywhere between one and five years. If your cartridges have seen better days, it could be time to replace them.

So, you need a new cartridge filter element? We can help with that!

Mr Pool Man can assist you with our large range of cartridge filter elements. Though if you're drowning in a sea of cartridge filter choice unsure of the one you need, we've got you covered!

Check out our super helpful blog here which contains easy to follow instructions on not only how to correctly measure your existing cartridge filter, but how to use those measurements to find the right replacement cartridge for you by using our cartridge filter size chart.


If you get really stuck,
Contact us with a photo of your system and/or the dimensions of your original cartridge filter element (length, width and hole width) and we'll be able to find it for you.

Do you know the specific model of your filter? Click here to see all of the filters in our collection. 

Davey Easy Clear EC 1000 Pool Filter Cartridge - Water TechniX Replacement Element-Mr Pool Man

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Now if you have a Sand Filter, these are the questions that you have to ask:

When was the last time you back washed your sand filter?

If it's been a few weeks or months between back washes (depending on the usage of the pool) your sand filter could be due for a good backwash. The general rule of thumb is to backwash once a fortnight. Chances are, you'll notice that the water that comes out of your filter during the backwash is very brown and dirty. This means that you should be doing it a little more often! Let the backwash run for 2 minutes or until the water turns clear. Set the handle back to filter and you're good to go.

When was the last time you changed the sand or media in your filter?

Filter sand lasts for anywhere between five and ten years. If you're back washing your filter and still noticing dirty water coming out after 2 to 3 minutes, or no clarity in your water following the backwash at all, this could mean it’s time to change the sand or media

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2. Use a Pool Clarifier

Pool water clarifiers are a good quick fix, but they should not be used if you have a cartridge filter as it will clog the paper pleats, leaving you needing to replace your cartridge filter element. Pool clarifiers work to gather the tiny particles that have made your pool water cloudy, bringing them together to create bigger particles that will be easier for your filter to pick up. They are a form of a coagulant. Most swimming pool chemical retailers will carry more than one form of swimming pool clarifier. Confirm if the chemical is a coagulant and you will be well on your way to a crystal clear swimming pool.

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3. Use Pool Flocculant (Floc)

A chemical known as flocculant, or floc, is a good idea if you’re in a rush, or would like to see your swimming pool water cleared quickly. Again, flocculant should be avoided if you are using a cartridge filter as it will clog the paper pleats. You can use it in an emergency, but be prepared to replace your cartridge filter element in the weeks to come.

Let's say you have a pool party tomorrow and your swimming pool is cloudy. By using pool floc and a little extra work on your part, you can clear your cloudy swimming pool overnight. Pool flocculants work by gathering all the particles that are making your pool water cloudy and sending them to the bottom of your pool, creating a cloud of particles on the floor of your pool. Unlike a water clarifier, this chemical will not help your filter trap the particles as they settle at the bottom of your pool.

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Once the particles have settled, you will need to manually vacuum them out of the pool using your pool pump instead of an automatic pool cleaner. When vacuuming, you want your filter setting to be on the ‘waste’ or ‘backwash’ setting if you are using a sand filter.

The idea is to vacuum the cloudy water right out of your pool, as putting that much dirty water through your filter will not work, sending the dirty water right back into your pool. By vacuuming out to “waste,” it will never run through your filter system. You will lose a fair amount of water from your pool, so be sure to keep a fresh hose of running water in your pool during vacuuming.

A manual vacuum must be used for this process. Automatic pool cleaners will not work and will end up blowing the larger particles formed at the bottom of your pool, right back up. It is a difficult process and a lot of water is wasted, but it will clear your pool in 24 hours if done properly.

4. Vacuum Waste Out of Your Pool

Your pool’s main skimmer is located at the top of your pool, helping to clear the upper portion of your pool water. It does not help to collect the cloudy particles situated at the bottom of your pool. Knowing this, we need to help your filter get to those particles.

Simply hook up your manual vacuum cleaner as if you were about to vacuum your pool, but instead of using it as per usual, leave the vacuum centred at the bottom of your pool and turn it upside down. Now your pool filter will be pulling water from the bottom of your swimming pool and releasing the clean filtered water at the top.

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What method would we recommend?

Number one, checking your filter, is the clear winner in our eyes. Having a good quality filtration system and staying on top of cleaning your system regularly will help you to avoid cloudy pool water.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Head over to our Contact Us page and drop our friendly team of pool pro's a line. 

Happy swimming :)

Featured Products throughout this blog

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Water TechniX Flexi Vacuum Head-Mr Pool Man

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For More In-depth guides on how to perform the advice listed above, check out these other blog that our experts have put together.  

How to vacuum a pool manually and save time and money.

How to backwash a sand filter and keep your filter in top condition.

How to test and fix pool equipment to extend their lifespan.

Green pool water? Here'show to get rid of pool algae in no time.

How to get rid of black spot algae, the most stubborn type of algae.

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Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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Post author:

Tom Hintze

Head of eCommerce & Operations at Mr Pool Man,
Co-Founder at Water TechniX

2 comments

  • Thankyou for the advice. I learnt something new here after having my pool for over 10 years.

    Sam Curulli on

  • thank yo for this leadership in pool management for the self managed owner. At this juncture, I do not necessarily require any pool related resources, but will make “Mr Poolman” my first port of call.

    Frank Malkoun on

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