API® Tap Water Conditioner instantly detoxifies tap water, allowing you to add fish to your aquarium (or return them after a water change) immediately. API Tap Water Conditioner removes chlorine from aquarium and tap water, detoxifies heavy metals, and can be used in both fresh and saltwater. This highly concentrated formula treats up to 600 US gallons with just one dose, making your aquarium a safe environment for your fish. >> Add 1 ml for every 20 gallons of aquarium water.