PureBLUE Pond Dye limits the amount of sunlight in a pond. We manufacture pureBLUE using the densest, commercially available dye on the market. When finished, it is up to 20% more powerful than most other gallons and at least that to all quarts (so called super quarts). One gallon will dye a one-acre pond 4 ft. deep depending on flow through, etc. for 5-6 weeks. It is a very natural blue, and not a light tropical tint.