CrystalClear PondShock is an excellent alternative to chemicals to clear your pond water fast. The organic ball contains billions of all natural, live bacteria and enzymes designed to rapidly break down ammonia, nitrites and organic waste. In the spring, it can jump-start biological filters when water quality issues escalate or before you introduce new fish into the pond. Use once a month or as needed when water temperatures are above 50°F. Safe for all aquatic life.