Clears Cloudy or Hazy Aquarium Water! Clear cloudy or hazy aquarium water in just a few hours with TetraAqua Water Clarifier. Safe for all freshwater aquariums, TetraAqua Water Clarifier is phosphate-fee. It will not affect bio-filtration, pH, or any other water parameters, and it is safe for fish and plants. Unlike many clarifiers on the market, Tetra’s formula is safe for fish even in very soft water (low KH) conditions. One teaspoon treats 10 gallons.