This superior line of natural pond and lake dyes are environmental friendly, nontoxic, water-soluble dyes that are formulated to reduce sunlight penetration and bring a natural black or blue appearance to your pond, lake or water features. These earth friendly ingredients are not only aesthetically pleasing but also helps your pond, lake, or water feature(s) by filtering the red/orange and blue/violet spectrum from the sunlight which is most often associated with algae and other aquatic plant growth.