Kent Pro Clear Freshwater produces and maintains crystal clear aquarium water without affecting pH. Whereas competing products may clog the fishes gills, suffocating them, Kent Pro Clear uses a blend of high tech polymers that will safely flocculate any algae, dirt, bacteria or other cloudy water causing particles. It is also safe for sensitive plants, which can be damaged by some competing products. Contains no phosphates, nitrates, or silicates to cause undesirable algae or slime growths. Not an algaecide. 100% biodegradable.