CaribSea Aragonite Hawaiian Black Sand contains authentic reef sand and never needs replacing. Complete with specially selected marine bacteria, this sand helps coral growth and works to eliminate nuisance algae. Contains marine bacteria to suppress \"new tank syndrome\" and compress ammonia cycles. Reduces nitrates Helps maintain proper pH levels Maintains calcium and alkalinity Made in USA Ingredients: Biogenic Aragonite and other Marine Carbonates Greater than 99%. Comprised of Aragonite Coated Grains, Ooids, Halimeda Incrassata, Halimada Favulosa, Goniolithon SSP, Lithothamnium SSP., Cerithidae SSP. (Gastropod Mollusk). Benthic Foraminifera SSP., Homotrema Rubrum Pelecypoda (Bivalve Mollusk), Echinoderm Fragments Directions for Use: Use one pound of sand per gallon of seawater.For deep sand beds, use two pounds per gallon. Do not rinse. Slowly introduce fish to the aquarium with the first three weeks. Do not exceed one inch of fish per five gallons of water, while introducing fish. Caution: Do not place substrate on top of existing substrate in the aquarium as it can be damaging to the aquatic life. Net Wt. 20 lbs/9,072 kg