Ecosystem Aquarium FRESHWATER Miracle Mud 2 is the original refugium mud substrate developed by Leng Sy in late 1989. Miracle Mud is comprised of up to 80% oceanic mud, harvested from deep ocean water and then dried on land. The remaining 20% is a formulation of minerals and trace elements that make Miracle Mud a true MIRACLE. Miracle Mud continuously replenishes the mineral and trace element concentration in the aquarium, making this the most comprehensive filter medium available. Miracle Mud is the most efficient denitrifying filter medium for the money. While other comparable products require a minimum 6-inch deep sand bed for denitrification to occur, you will need only 1 inch of Miracle Mud, making it the least expensive filtration medium available today. Miracle Mud reverses Hole-in-the-Head disease. Miracle Mud helps maintain the vibrant coloration of discus, cichlids and tropical fish in freshwater aquariums. 2 lb Size