Keep your fish happy and healthy with the Filter Aid Safe Water Solution from King British. This solution helps to maintain a healthy environment for your fish to happily swim around in. A weekly addition to your tank this solution uses various nitrifying bacteria to remove ammonia and nitrite that could damage your fish. This easy to use solution is effective in a wide range of water conditions; pH, hardness, temperature and salinity and is suitable for use with tropical, cold water, and marine fish.