AQUA ESSENTIAL water conditioner is a highly concentrated all-in-one water conditioner that instantly makes tap water safe for fish by removing chlorine, chloramine and detoxifies heavy metals commonly found in tap water. AQUA ESSENTIAL water conditioner instantly removes toxic ammonia, nitrate and nitrite levels in freshwater, saltwater and planted aquariums. Toxic ammonia continually released by fish through their gills, urine and solid waste. Uneaten food and decaying organic matter also add ammonia. Small amounts of ammonia stress fish; large amounts of ammonia will kill fish. This unique formula binds with ammonia, nitrite, and nitrate rendering them non-toxic and allowing the biofilter to more efficiently remove them. Use at start-up and whenever adding or changing water or when tested levels of ammonia, nitrates or nitrite are high. When adding, transporting or quarantining fish, we recommend using API STRESS COAT water conditioner which is ideal for use with AQUA ESSENTIAL water conditioner.