Contains one (1) API AQUA ESSENTIAL Water Conditioner 4 ounce bottle; treats up to 1,180 U.S. Gallons WORKS INSTANTLY: Highly concentrated aquarium treatment works instantly to remove harmful chemicals, making tap water safe for fish in freshwater and saltwater aquariums; Reduces the risk of fish loss when starting or maintaining a fish tank DECHLORINATOR: Removes chlorine, chloramines, heavy metals which are found in tap water and can cause gill and tissue damage, breathing difficulty, stress and fish death AMMONIA DETOXIFIER: Detoxify 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 NITRITES AND NITRATES REMOVER: Produced by fish waste and uneaten fish food, nitrites inhibit respiration and suppress the immune system at low levels, while high levels cause suffocation; Nitrates can be harmful to fish and lead to algae growth HOW TO USE: Use when adding or changing water, and when ammonia, nitrates or nitrites levels test high; No risk of overdosing; We recommend to conduct a water change after 24hrs and before re-dosing aquarium; Does not affect pH