African Cichlid Substrates Bio-Activ Live Cichlid Sand Aquarium, 20-Pound, Natural Black Contains live bacteria to quickly stabilize your tank & Immediately removes nitrogenous waste (Ammonia, Nitrite and helps remove Nitrate) This product is natural not artificial, prevents bio-fouling & Restores natural organic balance Contains live Heterotrophic and Autotrophic bacteria to provide a proper inorganic balance Contains live Chemolithotrophic bacteria All Bacteria are preserved in their natural live state