If you have a saltwater aquarium and you would like to minimize the amount of maintenance you have to perform in order to optimize your bacteria populations and suppress algae growth, CaribSea Arag-Alive Hawaiian Black Aquarium Gravel is the perfect solution for you. It features specially selected marine bacteria that have been engineered to suppress "New Tank Syndrome" and compress ammonia cycles. It also helps maintain a proper pH of 8.2 without the constant addition of chemicals for the life of the aquarium making this aquarium sand safe for all invertebrates. Use this aquarium sand to discourage the growth of nuisance algae by creating and supporting biological balance to your saltwater aquarium. This aquarium gravel also aids in the growth of corals and never needs replacement making maintaining your "showstopper" of an aquarium even easier. Why use ARAG-Alive? Just pour this "real" gravel into your aquarium and you are all ready to go! Ideal sand for:Berlin Systems Plenum Systems Nitrate Reduction Beds Sumps & Refugiums Fish Tanks Reef Tanks Birogenic and Clastic Grain Compostion: Biogenic Aragonite and other marine carbonates greater than 99%. Comprised of aragonite coated grains, ooids, Halieda Incrassada, Halimeda Favulosa, Goniolithon SSP, Lithothamniom SSP, Cerithidae SSP (Gastropod Mollusk), Benthic Foraminifera SSP, Homotrema Rubrum Pelecypoda (Bivalve Mollusk), Echinoderm Fragments. Aragonite Elemental Assay:Calcium (Ca)-381,000 ppm Carbonate (CO3)-590,000 ppm Strontium (SR)-7,390 ppm Magnesium (MG)-1,050 ppm Molybdenum (MO)-56 ppm Potassium (K)-56 ppm As well as Barium (BA), Manganese (MN), Iron (FE), Sulfur (S) and other essential trace elements.