Aqua Ultraviolet AAV10057 Quartz Sleeve UV Sterilizers for Aquarium, 57-watt Natural Gravel, Natural Sand and Natural Coated Sand 100% Acrylic Coating, Colorfast Non-toxic, will not alter the chemistry of your aquarium water Recommended Uses: Fresh & Saltwater Aquariums, Ponds, Terrariums, Gardens, Potted Plants, Vases, Ash Trays, Crafts & Hobbies