Substrate recreates the african rift lake environment and is complete with mineral. Buffers automatically for the life of the aquarium. Makes cycling a new aquarium faster and safer! Creates a natural biological balance. No rinsing required – packed in water conditioning solution for immediate results. Maintain the high pH African Cichlids need without the constant addition of chemicals. Contains live water purifying bacteria. Available in both fine and coarse grading. Fine grade is for small cichlids and featherfins; coarse grade is for all others. Coarse can be used with or without an undergravel filter. Dark substrate color encourages rich coloration in fish. High internal surface area allows more room for water purifying bacteria to thrive. 20 pound bags.