CaribSea African Cichlid Mixes can help to recreate a variety of environments. The natural colors encourage natural coloration of your fish. Cichlid Mixes naturally buffer your aquarium water with aragonite, simplifying the process or replicating the water parameters of the great African rift lakes, and eliminating downward drift in pH in established tanks. Seasoned hobbyists appreciate the ease with which water quality is maintained with these beautiful substrates. The 20 pound bag of African Cichlid Mix Original has a typical size between 5.0 mm and 10.5 mm and features an average density of 70 pounds per cubic foot.