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Cloudy pool water is caused by 4 common pool issues: poor filtration, low chlorine levels, poor water chemistry, or contaminants in the water, like debris or algae. Here’s a step-by-step guide on how to fix these common issues, and how to clear up a cloudy pool fast using a clarifier or flocculant.
You can watch the quick video tutorial below. Or keep reading for the complete cloudy pool water troubleshooting guide.
This is the ultimate guide to keeping your pool sparkling clean throughout the year that contains everything you need to know about taking care of your pool the right way.
Poor filtration, low chlorine levels, poor water chemistry, and outside contaminants cause cloudy water. Here’s how to troubleshoot each one of these issues.
Filter problems are the main cause of cloudy pool water. If your filter isn’t functioning properly, then it can’t remove the tiny contaminants that cause cloudy pool water.
SOLUTION: Keep your pool’s circulation system flowing with regular cleaning, maintenance, and run times. Check for the following filtration issues:
Pathogens, bacteria, and cloudy water form when there’s not enough chlorine to sanitize your water. Chlorine levels can drop if there’s lots of debris like leaves in your pool.
Also, if there’s a build-up of bodily contaminants like sweat or sunscreen, or if your water is exposed to the sun’s UV rays and your chlorine is not properly stabilized.
SOLUTION: Test your free chlorine and combined chlorine levels, add shock to rebalance your chlorine levels, and add cyanuric acid to stabilize a sun-exposed pool.
High levels of pH, Total Alkalinity, and Calcium Hardness can form scale on your pool surfaces and inside your plumbing. This can lead to pool filtration, bacteria growth, and cloudy water. And poor water chemistry makes it more difficult for your chlorine to function well and kill contaminants.
The proper pool water chemistry levels are:
SOLUTION: Test and balance your pH, total alkalinity, and calcium hardness levels.
Contaminants, particles, and small debris in your pool can cause cloudy water. This is especially common during the springtime. Early-stage algae growth may also cause cloudy pool water.
SOLUTION: Treat algae in its early stages by cleaning and shocking your pool. Test, balance, and clean your water after a rainstorm or when debris or pollen accumulates in your pool.
Tired of cloudy water and want to learn how to never deal with this problem again? Check out our pool maintenance video course today!
If you’ve tackled these common problems and you want to fix cloudy pool water fast, you can use either a pool clarifier or pool flocculant (aka
Pool clarifier uses your pool filter system to clear up the cloudy water. This is the easiest method for clearing cloudy pool water, but it takes a few days depending on your pool filter system’s power. A pool clarifier works with any filter type and works best with milder cloudy water issues.
Remove large debris with a heavy-duty skimmer. Brush your walls well with a stiff pool brush, then vacuum manually.
Do not use an automatic pool cleaner. It won’t properly suck up finer debris. Then vacuum your pool. But if you think you’ve got an algae problem, be sure to check out our guide on how to get rid of pool algae here first.
Test your water with test strips or a liquid test kit. Test strips are easier and quicker to use but are less accurate than a good liquid test kit. Or you can take a water sample to your local pool store. Then, adjust your pH and alkalinity as needed until your water is balanced.
A simple but effective liquid test kit for chlorine pools and hot tubs.
To eliminate any contaminants or chloramines in your cloudy pool water, add a high dose of chlorine by shocking your pool. If the cloudy water in your pool is due to a pool algae bloom, you’ll have to double or triple shock depending on the type of algae you have. And always shock your pool at dusk or night for maximum effectiveness.
Run your filter and let the shock dissolve overnight or for at least 8 hours. Then retest your water.
You’ll need to continuously run your filter over the next few days to help clear up the cloudy water. Then you can return to regular filter run times once your water is clear.
Your pool will clear faster depending on the type of filter you own. D.E. Filters, for example, filter out extra fine particles and will clear up cloudy water more quickly. If you have a cartridge filter, it will take a bit longer. If you have a sand filter, it will take the longest.
Your skimmer located at the surface of your pool can’t get to the debris or cloudy water at the bottom of your pool. To help all of your pool water pass through your filter, you can increase your pool’s circulation.
After your pool water has circulated and your shock has dissipated, it’s time to add your clarifier. Clarifier helps bind tiny particles into bigger particles that your filter can capture. Be sure to read the manufacturer’s instructions to make sure you’re adding the correct amount for your size pool.
Here’s our recommendation for a pool clarifier:
Clears cloudy pool water by combining particles, making it easier for your filter to remove. Great for all pools. Also compatible with salt water pools.
Clarifier works to clear mild cloudy pool water. Add it every other day as your filter runs until your water clears. If you have extremely cloudy water, you need to use a pool flocculant.
Pool flocculant, also known as
The coagulated particles cannot be removed by your filter, so you must be able to vacuum the water out of your pool while bypassing your filter media.
Test your water’s pH levels with test strips or a liquid test kit. Then, adjust your pH as needed, either with a pH increaser or
Pool flocculant binds the contaminants that cause cloudy pool water. Those large clumps then sink to the bottom of your pool. Be sure to read the manufacturer’s instructions to make sure you’re adding the correct amount of floc for your size pool.
Here’s our recommendation for a
A fast-acting formula that drops cloudy water particles to the bottom of the pool so you can vacuum it out. Safe for all pools.
Circulate the pool water with your filter system for two hours. If you have a multiport valve, set it to “recirculate” to bypass your filter.
After circulating the pool chemical for two hours, shut off the filter system for the next 8-12 hours to let the particles settle to the bottom of the pool. Make sure your automatic timer doesn’t turn on in the middle of the night.
You should now see a big cloud at the bottom of the pool. This means the
If you just vacuum your water through your filtration system, it’ll just blow right back in through the return jets. Instead, you have to vacuum the water out of your pool.
To do this with a multiport valve on your filter, just set it to the Waste option. This will send the pool water out of the backwash port as you vacuum. Keep a garden hose in your pool to refill your water while you vacuum.
If you don’t have a multiport valve, open the drain port on your filter and let it drain out as you vacuum.
Move the vacuum slowly along the bottom of the pool or else you’ll kick up the cloudy water. You may have to do this multiple times. Let the cloud resettle before continuing.
Because you’ve removed water from your pool, you’ll need to rebalance your water chemistry. Test your pool water using test strips or a liquid test kit and adjust your Alkalinity and pH. Once you get those levels balanced, add your chlorine.
Now that you’ve gotten the cloudy water out of the pool, you can start running your filter system normally (8-12 hours a day or however long it takes your water to cycle through your filter at least once).
Looking for more help with your cloudy pool water? Here are some common questions and answers.
Depending on how cloudy your water is, it may take 2-3 days for your water to clear. If you’re using a clarifier, you’ll need to run your filter 24/7, keep your water chemistry balanced, and add the proper amount of water clarifier every other day until it’s clear.
If your pool water is cloudy but your chemical levels are balanced, there are three likely reasons why:
Once you tackle the root of the issue, you can use a clarifier each week to keep your water sparkling and clear.
No, you should not swim in a cloudy pool. Cloudy pool water is full of contaminants and pathogens. There’s also an increased risk of drowning since swimmers can’t see the bottom of the pool.
Adding pool shock to an otherwise perfectly clean and balanced pool can even cause temporary cloudiness. This is common and it will dissipate over time as your filter runs. This can also happen if you use a cheaper shock. Be sure to use cal-hypo shock and read the instructions for the proper dosages.
High doses of chlorine, like pool shock, can cause temporary cloudiness as it kills contaminants. High levels of pH, alkalinity, and calcium hardness are more likely to cause cloudy water.
Rainstorms commonly cause cloudy pool water. They can wash contaminants into your pool water and the additional rainwater can throw off your pool water chemistry and lower your chlorine levels.
If your filter system is running properly and consistently, your chlorine levels are correct, your water is balanced and you’ve eliminated any algae growth, your cloudy pool can clear on its own. Otherwise, consider using a pool clarifier or
Matt is the founder of Swim University. He's been in the pool industry since 1993. His mission is to make pool care easy for everyone. Each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
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