This Bundle includes two items: Seachem Prime, 100 ml; and a 50 ml Measuring Cup. Seachem Prime is the complete and concentrated conditioner for both fresh and salt water aquariums. Prime removes chlorine, chloramine and ammonia. Ammonia is converted into a safe, non-toxic form that is readily removed by the tank's biofilter. It may be used during tank cycling to alleviate ammonia/nitrite toxicity. Seachem Prime also detoxifies nitrite and nitrate, allowing the biofilter to more efficiently remove them. It will also detoxify any heavy metals found in the tap water at typical concentration levels. Seachem Prime is for freshwater & saltwater aquariums. Use at start-up and whenever adding or replacing water. Use one capful for each 50 gallons of new water. The entire 100 ml bottle will treat 1,000 gallons. Non-acidic and will not impact pH. Prime will not overactivate skimmers.