Ways to Clear Cloudy Pool Water

1. Balance free chlorine (FC) levels.
2. Eliminate ammonia.
3. Get rid of young algae.
4. Monitor and balance pH and TA levels.
5. Correct calcium hardness (CH) levels.
6. Backwash filter or replace filtering agent.
7. Remove foreign particles and mineral deposits, scrub, and vacuum up the pool.

How Wrong or Imbalanced Pool Chemicals Cause Cloudy Water

Pool chemistry is the trickiest part of pool management. Using wrong chemicals or adding incorrect amounts are the major causes of cloudy water and may even lead to algae if extra care is not taken.

• Improper pH and chlorine levels: These are the most common culprits. The pH is not directly associated with cloudiness in the water, but it affects how chlorine and other chemicals work in your water. Very high pH usually leads to calcium not dissolving properly, causing cloudy pool water and calcium scaling both in saltwater and non-saltwater pools. On the other hand, if your pH gets too low, chlorine becomes very reactive and depletes very fast, forming lots of combined chlorine (chloramine), which turns the water cloudy and is ineffective in killing bacteria, algae, and other microorganisms in your water.
• High total alkalinity (TA): You also need to closely monitor changes in the level of TA. A high TA causes pH and calcium scaling, both of which are associated with cloudiness. The process of lowering total alkalinity involves aeration after adding muriatic acid. This process raises the pH to recommended levels.
• High calcium hardness: Very high calcium hardness levels in pool water will lead to excess calcium, which can't dissolve in water and accumulates in your pool. This causes cloudy water that won't clear up and calcium scaling inside the pool, and sometimes scales might clog your filter—leading to poor filtration and dirty or cloudy water. The only way to lower CH levels is to partially drain and refill your pool water. As such, remember to keep CH levels between 200 and 400 ppm all the time.
• Other chemical imbalances: High levels of accumulated phosphate and bromine and imbalanced stabilizers, such as cyanuric acid (CYA) might also cause cloudiness. If you are using cyanuric acid often, make sure that the CYA and free chlorine levels are balanced, because excess CYA will significantly reduce free chlorine. You might end up with severely cloudy water when bacteria converts cyanuric acid to ammonia. Use this chlorine/CYA chart to determine proper FC to CYA levels for your pool.

Remove Foreign Particles, Scrub, and Vacuum the Pool

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.

How to Clear Cloudy Pool Water Caused by Low Free Chlorine

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.

Cloudy pools are full of bacteria and pathogens that can cause urinary tract infections, stomach problems, and eye irritation. The most common bacteria found in cloudy or dirty pool water is E. coli.

It's just plain disgusting. A cloudy pool is an indication that the water contains high amounts of dirt, body oil, sunscreen, spit, urine, sweat, and other gross particles.

Which tool do you use to measure and control your pool chemistry?

I use a digital pool water test reader.

I use pool water testing strips.