Produces and maintains crystal clear aquarium water without affecting pH. Works without clogging fish's gills, suffocating them, or causing invertebrates to close up. Completely safe for all marine fish and invertebrates. It uses a blend of high tech polymers that safely flocculate any algae, dirt, bacteria, or other water clouding particles. Contains no phosphate, nitrate, or silicate to cause undesirable algae or slime growth. Not an algaecide and 100% biodegradable. 16 oz treats 4,700 gallons.