How To Fix Cloudy Pool Water

When you have a cloudy pool, it can be a very difficult and time-consuming process to get it clear. Sometimes, your swimming pool will turn cloudy overnight!

I’ll explain the reasons your pool got cloudy in the first place, then share a few methods on how to fix the cloudy water. It won’t be a difficult and time-consuming process if you follow these methods.

How to fix cloudy pool water -

    1. Why Do I Have Cloudy Pool Water? The filter could be clogged and dirty or there could be a chemical imbalance with the water chemistry
    2. How To Clear A Cloudy Pool? Utilising specific chemicals to clear the water along with general pool maintenance to clean the filter and replace
    3. Clean your filter! If you have a sand filter, you need to backwash! Otherwise the sand filter may require a media change. If you have a cartridge filter, your element will be very clogged, these commonly need replacing every season or two depending on the maintenance on them
    4. Vacuum waste out of the pool! Remove all settled debris out of the pool by vacuuming to waste, this ensures the suspended particles are completely removed from the pool!
    5. What method would we recommend?


Why Do I Have Cloudy Pool Water?

There are so many causes of cloudy pool water, but we have broken it down into three main causes.

1. The Pool Filter

Your filter system constantly cleans the water in your pool. Without it, you’re left with stagnant water that could become cloudy. Pool clarity is 9 times out of 10 linked to your filtration. If you are experiencing a cloudy pool, something's up with either your sand or cartridge filter.

2. The Environment

Everything around your pool can cause your water to be cloudy, that includes: weather, birds, construction, trees, gardens, the sun, people, and pool algae.

3. Pool Chemicals

An excessive amount of pool chemicals can cause your water to be cloudy. That includes: high pH, high alkalinity, high chlorine or other sanitisers, and high calcium hardness. Usually, running your filter like usual should help even these out over time, though if you do have an imbalance we'd recommend testing your water and fixing it.


How To Clear A Cloudy Pool

Once you have fixed all the possible problems that can cause your water to be cloudy, now we can work on a cloudy pool water fix.

Here are 3 ways to clear your cloudy swimming pool:

1. Check your filter!

If you have a Cartridge Filter:

When was the last time you cleaned your cartridge?

If it was a while ago, take your cartridge out and give it a good hose down. Tip: If you are after a thorough clean, soak your cartridge in a tub of clean water with a cup of Nappy San overnight (the same stuff that you use in the laundry in the pink tub). Nappy San contains the same cleaning chemicals as your expensive cartridge filter cleaning chemicals. Follow this by a good rinse with your garden hose the next day.

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

As your cartridge filter is made out of layers of paper, these two chemicals will clog your cartridge to the point of no return and should be avoided at all costs if you use a cartridge filter as your filtration system. You can use them if it's an emergency, though be prepared to be replacing your cartridge filter element(s) when you're done.

How old are your cartridge filter element(s)?

Depending on what chemicals pass through them, pool usage, how often they are cleaned/maintained etc, cartridge filters have an average life span of anywhere between 1-5 years. If your cartridges have seen better days, it could be time to replace them.

Mr Pool Man can help you with this with our large range of cartridge filter elements. Can't find the one you need? Contact us with a photo of your system and/or your dimensions of your original cartridge filter element (length, width and hole width) and we'll be able to find it for you.

If you have a Sand Filter:

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) you could be due for a good backwash. Rule of thumb is to backwash once a fortnight. Chances are you'll notice that the water that comes out during the backwash is very brown and dirty, this means that you should be doing it a bit more often! Let that backwash run for 2 minutes or until the backwash water turns clear. Set the handle back to filter and you're good to go.

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

Filter sand lasts for anywhere between 5-10 years. If you're back washing your filter and you're still noticing dirty water coming out of the backwash after 2-3 minutes or no clarity in your water following the backwash, this could mean sand change time.

2. Use A Pool Clarifier

Pool water clarifier's are a good quick fix, though should not be used if you are sporting a cartridge filter (it will clog the paper pleats to the point of no return, leading to replacing your cartridge filter element).

Pool clarifiers work to gather the tiny particles that are making your pool water cloudy and bring them together to create bigger particles so that your filter will have a better chance of picking it up. This is called a coagulant which is a term used when describing blood clots.

The particles alone will have a hard time being picked up by your pool filter, so this chemical “clots” them together and your filter now will be able to trap them.

Most swimming pool chemical retailers will carry more than one form of swimming pool clarifier. Just ask if the chemical is a coagulant and you will be well on your way to a crystal clear swimming pool.

Sold out

 3. Use Pool Floc (Flocculant)

A chemical called Floc or Flocculant is a great idea if you’re in a rush, or would like to see your swimming pool cleared up quickly. Again, a flocculant should be avoided if you are sporting 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.

Lets say you have a pool party tomorrow and your swimming pool is cloudy. By using Pool Floc, you can clear your cloudy swimming pool overnight (with a little extra work on your part).

Pool Flocculants work by gathering all the particles, that are making your water cloudy, and sending them to the bottom of your pool, creating a huge cloud on the floor of your pool. Unlike a water clarifier, this chemical WILL NOT help your filter to pick up the particles, because all of the cloudy pool particles are now settled at the bottom.

At this point, you will need to manually vacuum up that cloud using your pool pump, not an automatic pool cleaner. When vacuuming, you want your filter setting to be on the “waste” or “backwash” option if you are using a sand filter.

The idea here is to vacuum up the cloudy water right OUT of your pool, because putting that much dirty water through your filter WILL NOT work and will send that dirty water right back into your pool.

By vacuuming out to “waste,” it will never run through your filter system. You are going to lose a fair amount of water in your pool, so make sure to keep a fresh hose of running water in your pool during vacuuming.

Also, you must use a manual vacuum for the process. Automatic pool cleaners will not work and will just end up blowing the cloudy you created at the bottom of your pool, right back up. Again, it is difficult and a lot of water is wasted, but it will clear your pool in 24 hours if done properly.


4. Vacuum waste out of the pool!

Your pool’s main skimmer is located at the top of your pool and helps to clear the top, which does not help to collect the cloudy particles that are at the bottom of the pool. Knowing this, we need to help the filter get to those particles.

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

What method would we recommend?

Number 1 is the clear winner in our eyes. Having a good quality filtration system and staying on top of cleaning that system regularly (fortnightly) will provide you with clarity in your water.


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Post author:

Tom Hintze

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


  • 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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