Prime is the complete and concentrated conditioner for both fresh and salt water. Prime removes chlorine, chloramine and ammonia. Prime converts ammonia into a safe non-toxic form. Provides essential ions and stimulates natural slime coat. Prime also detoxifies any heavy metals found in the tap water at typical concentration levels. When used during cycling, Prime enhances nitrate removal and does not cause a pH drop or overactivate protein skimmers. Great for setting up new aquariums, or when adding or changing water, or to remove nitrate. 16.9oz treats 5000 gallons of water.