Mechanical and biological filtration in one systemFilter cartedge can be changed and displayed in one whole piece.Easy setup, easy maintenance and effective performancePerfect for fresh and marine tank.It is a mechanical and bilogical filtering systemSpecial carbon cartidge to purify water, remove odor and offer housing compartment for the biological bacteriaBio Cartridge enhances biological filtration and guaranties optimum colonization of nitrifying bacteria Easy to use, fill up water and plug on. Easy to maintain. Every 2 months replace a new carbon cartridge to achieve best result.