Cloudy water happens for a variety of reasons, including stirred up sand or gravel, bacteria blooms, or floating algae blooms resulting in green water. Water clarifiers do not clear every possible water cloudiness issue, sometimes it is only proper filtration and time will clear up the issue. However, many products do work wonderfully to clear up cloudy water problems. An aquarium water clarifier is meant to be a temporary solution to the cloudiness problem while the tank conditions equalize. These chemical binding liquids are referred to often as a flocculent.