Milky or cloudy pool water is often caused by a pH imbalance, inadequate filtration or a chlorine deficiency. Each of these conditions is simple to check and can be easily remedied.
Checking for inadequate filtration requires a visual inspection of the filter. Broken or missing pieces should be replaced immediately. Backwashing the filter may help the situation and if all else fails, add a clarifier to the water for easy filtration.
A pH imbalance will occur when the pH rises to 7.6 or above. When this happens, it causes calcium to form a scale, making the water appear cloudy. Adding the necessary chemicals to balance the pH will take care of the problem.
If the chlorine level of the pool is too low, algae and other organic materials can cause milky water. Chlorine levels should always remain at between 1.0 and 4.0 ppm.