Suitable for coldwater & tropical aquariums removes chlorine chloramine & heavy metals reduces stress.Tap Water Safe removes chlorine and other halogens chloramine and heavy metals found in tap water which are toxic to fish. Tap Water Safe also contains a special protective coating that reduces stress caused by transportation of fish. If adding fish to your aquarium or carrying out a water change use in conjunction with NT Labs Filter Starter to help your filter cope with the increase in fish waste or replenish the filters bacteria.