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. >> Add 1 ml. for each 20 gallons of aquarium water.”