Why Is Pool Water Cloudy After a Shock Treatment?

The most common reason for cloudy pool water after a shock treatment is the presence of calcium hardness, which is also known as hard water. Most shock treatment solutions contain calcium hypochlorite as an active ingredient, which causes calcium levels to rise, producing water scale deposits.

Using shock treatment solutions that contain calcium hypochlorite as an active ingredient should not be eliminated; they are the only treatment solutions that properly eliminate the presence of algae. Alternative solutions to reducing calcium levels include using the backwash option that comes with pool pumps, adding flocculants, or adding certain acids that can restore the balance of the pool's water as determined by the saturation index.