Having too much chlorine in your swimming pool water can cause it to become cloudy. Having too many chemicals in your water can throw off the delicate pH balance. Using too much of any pool chemical can cause cloudy water. High pH, high chlorine, and high alkalinity are all possible culprits. If your calcium hardness is too high, it can cause problems as well. In order to find the cause, you will need to check the chemical levels and adjust them accordingly