Pet Petco White Aquarium Sand, 5 lbs. Stone, Gemstone, Decoration, Design, Non-toxic, Pebble Supply Store/Shop Assists in breaking down waste Adds depth and beauty to aquariums, water gardens, ponds and terrariums Made of non-toxic fish safe materials and colors Safe for use in freshwater and marine environments For optimum results, use 2 lbs. of sand per every one gallon of water