Api tap water conditoner treatment removes toxins from tap water instantly, so you can add fish to your aquarium or add them back after a water change immediately. Api tap water conditioner treatment dechlorinates aquarium and tap water, detoxifies heavy metals, and may be used in both fresh and salt water. This super concentrated formula treats up to 600 us gallons with just one ounce, making your aquarium a safe environment for your fish. Safety Information Please Read Instructions Before Use Directions Add 1 ml. for each 20 gallons of aquarium water.