Crystal Blue Ocean Blue Lake & Pond Colorant uses a proprietary formula to give to your lake or pond a beautiful turquoise blue color all year long. 100% safe for humans, fish, livestock, pets, birds, swimming, potable water and irrigation. Maintains color and clarity for up to 30 days. Helps settle out dissolved solids. 1 gallon treats 1 surface acre, 4 – 6 feet deep.