The simple one-step patented formula to perfect water. For tropical fish and goldfish. Eliminates chlorine & chloramines. Neutralizes harmful ammonia. Regulates pH to 7.0. Wardley Safe2O instantly conditions tap water when setting up a new tank or when changing or adding water to the aquarium. Wardley Safe2O is not compatible with Nessler reagents. Treats: Up to 236 gallons (894 liters).