The perfect hang-on filter for aquascaping aquariums. The Triple Action filter consists of two cartridges: the first is filled with CrystalMax, a highly porous biological filter media made of sintered glass. This acts like a sponge for microorganisms, breaking down waste and other harmful substances quickly and efficiently. The second cartridge is filled with filter foam with a 100% open structure for optimal filtration, and activated carbon, which removes organic waste, chemicals, and dyes from the water.