Your filter may need to be backwashed in the case of a sand filter or your pump may need to run for a longer duration daily. With a cartridge filter your cartridges may need to be cleaned or your chemicals may be out of balance. Cloudy pool water is usually an early indicator of algae formation however, cloudy water can be caused from alot of factors. Too high ph, bad pool circulation, not enough chlorine, too high calcium are a few common reasons. With proper pool chemistry a UV pool sanitation system can help maintain your pool and make it more enjoyable and healthier to swim in.