CrystalClear Pond and Lake Dye keeps water clear and provides plenty of shade for UV rays all year long. Each one-gallon pond and lake formulated pond dye treats up to one surface acre with an average depth of 4' - 6' fee deep for several months. No mixing is required, the dye can be poured directly from the shoreline and it is safe for all aquatic life. For year-long beauty, pond dye can be applied early in the spring and added as needed. Choose from two colors: TrueBlue for a vibrant blue color or DeepBlue for a dark blue color.