The complete African cichlid substrate! Minereralogically complete! Contains Aragonite! Maintains the high pH African Cichlids need without the constant addition of chemicals. Buffers automatically for the life of the aquarium! Adds calcium, magnesium, carbonate and more! Dark color encourages the richest coloration in fishes. Unique composition re-creates the African Rift Lake environment. High internal porosity for maximum biological capacity - keep more fish healthier... longer! Biologically complete! Contains live water-purifying bacteria that makes cycling a new aquarium faster and safer! 4 equals 1! You would have to buy 4 bags of ordinary gravel to equal the surface area available for water purifying bacteria in this one bag of Eco-Complete African Cichlid Substrate! Creates a natural biological balance to discourage nuisance algae. No rinsing! Packed in water conditioning solution for immediate results!