Improves filtration in any make or model fluidized bed filter. Angular shape provides higher surface area compared to round. High surface area-features 71 sq. ft. per lb. of available surface area for bacterial growth. This package provides 214 sq. ft. Self cleaning function from sand grains colliding with greater frequency. This bumping knocks debris off sand grains providing new areas for bacterial growth to occur. This special mixture of sand is easily fluidized even with small energy efficient pumps. For use in fresh or saltwater aquariums.