Not only is cloudy pool water uninviting, but it could also be breeding dangerous bacteria or damaging your pool. So to avoid expensive repairs and illnesses, you need to figure out the cause of a cloudy pool before you can fix it.
Common Causes of Cloudy Pool Water
Usually, it takes some time for your pool water to turn cloudy. Some water problems can cause noticeable cloudiness to occur seemingly overnight. So what the heck happened?
1. Low Sanitizer Levels
Low levels of free chlorine, bromine, or another sanitizer in your water can lead to bacteria growth and increased stress on your filter. You might have low sanitizer levels because:
- Natural debris (leaves) use up your sanitizer attacking it. If the debris isn’t removed quickly by you or your filter, it’ll gobble up your sanitizer.
- Sweat, sunscreen, beauty products, and even urine deplete chlorine.]
- The sun’s ultraviolet rays break apart the sanitizing hypochlorite ions created when you add chlorine to your pool, causing them to evaporate into the air around your pool.
So while the pool chemicals are busy attacking a pile of rotting leaves on the pool floor, they’re less effective at quickly killing hazardous pathogens and bacteria, such as E. coli, making your cloudy pool water ugly and dangerous.
Before you adjust your chlorine levels, make sure to get your pool water tested. If you have a chlorine or salt water pool, you want to make sure your free chlorine and combined chlorine reads match at around 1-3 ppm (parts per million). You can either use test strips, a liquid test kit, or take a sample to your local pool supply store. Here’s our complete guide on how to test your pool water.
To quickly bump up your chlorine sanitizer levels you can shock your pool using calcium hypochlorite shock. We have a complete tutorial on how to shock your pool. And a guide on how to properly add chlorine to your pool.
2. Poor Filtration Problems
Problems with pool filtration is the main cause of cloudy pool water. It’s mostly preventable by keeping the circulation system healthy. Make sure:
- Your pool filter doesn’t have a clog or build-up.
- Your pool pump isn’t dying.
- Your pool filter media doesn’t need to be replaced. For a sand filter, you may need to change your filter sand. For a DE filter, you can replace the diatomaceous earth (D.E.) powder. And for a cartridge filter, just rinse or replace the cartridge inside.
- And you’re running your filtration system for at least 8 to 12 hours a day.
You can improve your pool filtration by simply backwashing the filter (if it’s a sand or D.E. filter) or cleaning/replacing the cartridge inside. You can also empty your skimmer basket and pump basket if it has any debris. If you’re having trouble with a clogged pool skimmer, check out our troubleshooting guide.
Your pool circulation system can fail you as it gets older, or it can be damaged by wonky chemical levels or neglect. When your filter can’t remove tiny particles in your water as well as it should, you get cloudy pool water.
3. Poor Water Chemistry: High pH Levels, Alkalinity, and Calcium Hardness
High pH, Total Alkalinity, and Calcium Hardness can form scale on pool surfaces and inside plumbing while making it more difficult for your sanitizer to work. This can also cause filtration problems, bacteria growth, and cloudiness.
If you have high alkalinity or pH, you can lower it with either pH decreaser or muriatic acid.
If you have high calcium hardness, the only thing you can do is dilute your pool water with fresh water from your garden hose. You can drain water from your pool by backwashing the filter or removing the drain plug from the filter while the pump is on. Then, just add fresh water to replace it.
Note: Diluting your pool water will affect all the water chemistry levels. So make sure you get it tested again.
And if free chlorine levels are lower than your total chlorine levels, you can also end up with a lot of chloramines—the byproduct of chlorine sanitizing—which can be irritating and even corrosive. This chemical imbalance is reason enough to learn how to clear cloudy pool water.
Make sure to get a swimming pool water test and adjust your pool chemical levels to hit these perfect water chemistry ranges:
- pH: 7.4 to 7.6
- Alkalinity: 100 parts per million (ppm) to 150 ppm, with 125 ppm being ideal
- Calcium Hardness: 175 ppm to 225 ppm, or 200 ppm to 275 ppm for concrete and plaster pools
- For Chlorine Pools: 1 ppm to 3 ppm
- For Bromine Pools: 3 ppm to 5 ppm
- For Biguanide Pools: 30 ppm to 50 ppm
- For Salt Water Pools: 0.5 ppm of chlorine
- For Mineral System Pools: 0.5 ppm of chlorine
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Method 1: How to Fix Cloudy Pool Water with Pool Clarifier Chemical
Ready to get your pool water back to its former crystal clear glory? This method uses your pool filter system to clear up the cloudy water. But it takes a few days or even longer depending on how powerful your pool filter system is right now.
This is the easiest method for clearing your cloudy pool. Let’s begin!
1. Give Your Pool a Deep Clean
Start by giving your pool a good scrub down. 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 for this job because it won’t properly suck up the finer debris that you need to get.
If you think you’ve got an algae problem, vacuum to waste. If you have pool algae, you should deal with that first. Learn how to get rid of pool algae here. And learn how to vacuum your pool to waste here.
2. Balance Your Pool Water Chemistry
Once you’re sure your water is as clean as it can be, test it or take a sample to your local pool store. To test it yourself, just use either 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.
Adjust pool chemicals as needed until your water is balanced. Use a chlorine stabilizer—also called cyanuric acid—to protect your chlorine levels.
A simple but effective liquid test kit for chlorine pools and hot tubs.
3. Shock Your Pool At Night
To get rid of all the gross and dangerous crud in your cloudy pool water, shock your pool. This mega-dose of chlorine (or non-chlorine shock for pools that use other sanitizers) will help eliminate cloudiness caused by bacteria, organic contaminants, and algae.
Note: 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 that’s invaded your pool. And always shock your pool at dusk or night for maximum effectiveness. Read more about that here.
Why is my pool cloudy after shocking?
Adding pool shock to an otherwise perfectly clean and balanced pool can even cause temporary cloudiness. But if you add the proper dose of shock, it can clear your pool right away if your pool water filtration and circulation are working properly.
4. Filter Your Pool Water 24/7
In order for this method to work, you need to keep you pool pump and filter running until the water is clear. Your pool filter is going to do all the work filtering out the tiny particles that are making your water cloudy.
Don’t worry, once the water is clear you can go back to running your pump and filter around 8-12 hours per day instead of 24/7.
Note: If you have a D.E. filter, your pool will clear faster. DE Filters pick up fine particles. If you have a sand filter, it will take longer because it doesn’t have the same filtering power as a DE filter. And if you have a cartridge filter, that’s right in the middle between the two other types of pool filters.
5. Use Proper Pool Circulation Tricks
The main skimmer is at the surface of your pool but it can’t get to the debris at the bottom (where most of the cloudy water is) unless you employ a few tricks.
- Position Your Return Jet: Point your return jet(s) slightly down and all in the same direction to spin the water creating a whirlpool effect. This will help churn the cloudy water up from the bottom of the pool to the top where your main skimmer can get it into your filter system.
- Use Your Bottom Drains: If you have an inground pool, make sure the main drain at the bottom is on and pulling water from the bottom of the pool into your filter system. This will speed up filtering and clear the pool water faster.
- Turn Your Vacuum Upside Down: If you have an above ground pool with no main drain, you can hook up your manual vacuum cleaner and turn it upside down at the bottom of the pool. This essentially created a bottom main drain in an above ground pool which will help clear the pool faster.
6. Use Pool Water Clarifier
Finally, you want to consistently add the proper amount of pool clarifier to the water. This will help bind a bunch of tiny particles into bigger particles that your filter will have a better chance of picking up.\
Every pool clarifier on the market is different, so make sure you read the bottle to make sure you’re adding the correct amount for your size pool.
Your filter can clear a cloudy pool. But your filter needs help picking up particles that are too small. A clarifier binds these particles together, so your filter can remove them easier.
How Long Does it Take For a Cloudy Pool to Clear?
Depending on how cloudy your water is, it may take 2-3 days for your water to clear. Just make sure you 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.
What happens if you swim in a cloudy pool?
It will actually help clear the water faster! Why? Because swimming improves water circulation. However, cloudy water presents a risk of drowning. So before you swim, make sure you can at least see the bottom of your pool, according to the CDC.
Method 2: Clear Cloudy Pool Water Fast with Pool Floc
This method is a lot more work for pool owners because it requires a lot of manual vacuuming to remove the cloudy water. But it’s the fastest method and recommend only if you need your pool clear in less than 1-2 days. Otherwise, I’d use the first method.
1. Add Flocculant (Floc) Your Pool
If you’re in a hurry and your cloudiness isn’t too bad, you can try using a pool flocculant. Once the floc does its job, all the suspended debris in your water will sink to the bottom of the pool.
You can follow the directions on the back of the bottle. But here’s the best way to make sure the Floc will work effectively:
- Add the correct amount of Floc to the pool water.
- Circulate the pool water using the filter system for two hours. If you have a multiport valve, set it to just “recirculate.” This bypasses the filter media so it doesn’t filter out the Floc before it has a chance to do its job.
- 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 kick back on in the middle of the night.
2. Vacuum The Water Right Out of The Pool
This is where all the hard work comes in. You now should see a big cloud at the bottom of the pool. This means the Floc collected all the particles that were making the water cloudy and sank them to the bottom.
Now you have to get that thick cloud out of the pool. But if you just vacuum it normally through your filter system, it’ll just blow right back in through the return jets.
Instead, you have to vacuum the water right 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. You’ll need to keep a garden hose in your pool to fill it while you vacuum.
If you don’t have a multiport valve, you can just open the drain port on your filter and let it drain out as you vacuum so it doesn’t come back into the pool.
Note: Move the vacuum slowly along the bottom of the pool or else you’ll kick up the cloud and you won’t be able to see what you’re doing. And you may have to do this multiple times. Let the cloud resettle before continuing.
Pool floc binds particles (and dead algae) that are making your water cloudy together and sinks to the bottom of your pool so you can easily vacuum out the cloudy mess.
3. Test, Balance, and Sanitize the Pool Chemistry
Once you’ve gotten the cloudy water out of the pool, you can start running the filter system again for 8-12 hours a day (or your normal schedule). Then, you should test the pool water using test strips, a liquid test kit, or take it to your local pool store.
Adjust your Alkalinity and pH first. Once you get those levels balanced, then you can add your sanitizer of choice (chlorine, bromine, etc.).
After that, you should be good to go!
Stop Cloudy Pool Water Before It Starts
Clearing up your pool isn’t a massive undertaking, but depending on the problem it can cost you a bit in chemicals and elbow grease. But you’ll appreciate it when you leave the cloudy pool behind and dive back into sparkling water.
Make sure the only clouds you see are the ones in the sky. Weekly testing and balancing, skimming and vacuuming, basic filter maintenance, and regular shocking will keep your pool healthy and clear all season long.
Happy Swimming!
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