Tetra® WaterClarifier clears cloudy aquarium water caused by overfeeding, gravel dust and other minute suspended particles. This phosphate-free liquid solution is safe to use in all freshwater aquariums. This effective formula works by causing small, suspended particles to quickly clump together. These larger particles are then removed during normal power filter operation. This formula is based on clarifiers used to treat drinking water. It’s safe to use with fish and plants and will not affect water pH levels in your aquarium.