When you have a cloudy pool, it can be a very difficult and time-consuming process to get it clear. 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.
Firstly, a thorough clean of your pool to remove any foreign particles and algae is the best way to start cleaning up the cloudiness of your pool. Scrub and vacuum your pool including all the surfaces. If you have algae present, shocking your pool will assist in removing the remaining algae growth.
Read our guide: What Causes Cloudy Pool Water?
1. Use a Chlorine Stabilizer
Low free chlorine levels are caused by heavy usage, heavy rainfall (which dilutes the chlorine), or hot sunny days when UV light oxidizes lots of free chlorine. If you have an outdoor pool, you can use a chlorine stabilizer, such as cyanuric acid, to prevent chlorine depletion as a result of direct UV light. Remember that cyanuric acid is very strong, and if it exceeds the recommended levels, free chlorine will disappear, and the water will turn cloudy and be at high risk of algae growth.
In summary, if your combined chlorine reads above 0.5 ppm, your water may turn cloudy and become unsafe for swimming. If this is the case, you need to shock your pool immediately to clear it.
Liquid chlorine or sodium hypochlorite is the best option for a daily free chlorine boost, because it does not affect pH, calcium hardness, and cyanuric acid in your water, which make pH, calcium hardness, and cyanuric acid scale high above the recommended levels—leading to cloudy water, metal stains, ammonia, algae, and other pool problems.
How to Know If Your Chlorine Is Imbalanced
The wider the range between free and total chlorine, the more combined chlorine (chloramine) is present in the water. Combined chlorine should always read below 0.5 ppm or just 0 ppm, if possible. This means you should test chlorine levels on a daily basis and adjust it as appropriate before there's excess chloramine, especially during the summer when it's hot and the pool is used heavily.
Safe pH Level for Swimming
The correct level of pH in a swimming pool should be between 7.4 and 7.8, with 7.6 being the ideal level.
2. Monitor pH and Total Alkalinity
The level of pH in pool water affects how all other chemicals function, including chlorine. When pH level gets too high, chlorine will become ineffective, and we all know how important chlorine is in a pool. High pH also makes water look dull, and it should always be within the recommended range.
How to Balance the pH in Your Pool
To lower pH, you need to use a pH reducer (pH minus), such as muriatic acid or sulfuric acid. Anything below a pH of 7.0 is too low, and apart from turning water cloudy, this environment brings about harmful bacteria causing ammonia and algae. To increase low pH levels, you need to use a pH Increaser (pH plus) with soda ash.
How to Balance Total Alkalinity (TA)
Finally, ensure that total alkalinity is within the required range of 80 ppm and 120 ppm to avoid bringing up pH levels and causing calcium scaling. To lower total alkalinity without extra equipment, add muriatic acid and aerate the pool to restore pH levels without having to add a pH increaser, which will increase alkalinity levels too.
3. Check Your Filter
A poor water-circulation system can also be a big problem. If your water cannot circulate properly, it will become stagnant and cloudy. To fix this problem:
Ensure that the return fittings (eyeball fittings) are turned to point down, which enables the water at the bottom of the pool to circulate properly. However, the circulation system will largely depend on how the pool was built.
Make sure you are using the right pump size to adequately clean the water.
Make sure the filtration system is running long enough. A filter should run 24/7 for the water to remain clean all the time. However, for home pools that are not busy, at least 8 -10 hours a day might suffice.
Remove particles that may be blocking your filter. Your filter system continuously cleans the water, and if it does not function properly, the water becomes dirty, cloudy, and may even develop algae. Large particles are fond of blocking filtration systems, especially diatomaceous earth (D.E) and cartridge pool filters.
Ensure that you regularly clean, backwash, or replace the D.E and cartridge filter medium as appropriate. Cartridge filters usually last 2,000 hours and should be replaced every 1-2 years, depending on usage.
Which Pool Filter Is Best?
There are three types of filters: DE (diatomaceous earth), cartridge (paper), and sand. Each has its own pros and cons. A DE pool filter is the most efficient when it comes to filtration, followed by cartridge, and the sand filters. Here is my detailed guide on types of pool filters, how to select the best one, and how to properly maintain it.
Private Pools
DE and cartridge filters are recommended for home pools and may not be the best when it comes to public pools (apartments or hotels) due to their tendency to clog. The filter medium for DE and cartridge filters also require frequent replacement.
Public Pools
A sand filter is always best when it comes to public or semi-public swimming pools, but the sand used in a sand filter also gets clogged and becomes ineffective, which may cause your water to be cloudy or dirty. Consequently, the sand should be replaced every year.
4. Use Pool Floc (Flocculant)
The environment and weather may also be the cause of cloudy water. To fix and prevent cloudy water, follow all of the best practices below.
Foreign particles, small and large, may find their way into the water, especially during spring. Body oil and sunscreen from swimmers also washes off in the water and accumulates in the pool, causing cloudiness. You can use nets to remove visible particles, and you may have to use pool clarifier to clear up the water when cloudiness persists. Also, I prefer using pool flocculant and vacuuming the pool to do away with fine particles that cannot be removed by leaf net or clarifier.
Algae also causes cloudiness in its early growth stages. To remove algae, scrub and clean the pool using a large leaf net and vacuum: Then do a pool shock to get rid of any remaining algae. Control the amounts of pH, chlorine, TA, phosphate, and other pool sanitizers to prevent algae growth.
Free chlorine depletes more quickly in full sunlight, but if trees and buildings are next to your pool, direct sun will be blocked. If your pool is in direct sunlight, consider using a chlorine stabilizer (CYA) and a pool cover when not using the pool.
Rain also contributes to cloudy water because it dilutes and therefore reduces free chlorine levels. All you have to do is test the chemicals, paying close attention to the chlorine levels, and adjust them as appropriate.
5. Shock Your Pool
You can use algaecide to kill early stages of green algae that might make your water appear cloudy, but the best method of getting rid of algae is to scrub and clean your pool using a large leaf net, vacuum, and kill algae with liquid chlorine shock.
You should only use algaecide once in a while for preventive measures and when green algae is just starting to show up—it is not useful when algae outbreak is immense and very visible.
Furthermore, if you have full green, black, or yellow algae, you may end up using a lot algaecide, which can be very expensive and the best result is not guaranteed like when you use liquid chlorine. Some algaecides may also cause foaming or deposit copper metal in your water when used in large quantities.
6. Use a Pool Clarifier
It’s always a good idea to use some sort of pool water clarifier weekly. 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.
It’s always a good idea to use some sort of pool water clarifier weekly. 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.
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