Ideally, swimming pools are meant to be crystal clear and ready for a refreshing swim any time of the day or night, but bodies of non-moving water tend to collect bacteria and algae which grow over time and can change the color of your pool. A green pool is a dirty pool and the level of effort put into keeping it clean depends on how long the buildup has been allowed to progress.

Causes of Green Swimming Pool Water

Chlorine is a chemical added to swimming pools to kill bacteria that can build up over time and lead to a discoloration of the water. Green water is most often a sign of algae, not necessarily bacteria, but different pools have different bacteria that can affect the water. If the pH balance of the water isn’t in the right place, it will allow bacteria to flourish, leading to further discoloration. If the pH level is too low, the water is acidic and over time, it will erode plastic and metal components. A pH level that is too high will not kill bacteria and will allow scale buildup of calcium and other minerals. A healthy pool is between 7.2 and 7.8 on the pH scale.