Combines mechanical, chemical, and wet/dry biological filtration functions in an innovative and efficient tank mounted external filter unit85 gph pumpRecommended for freshwater tanks and saltwater fish only tanks up to 15 gallonsProduct Sheet (pdf format in new window)The unique BioGrid plate provides a high surface area of biological filtration that is separate from the MechaniChem filtration cartridge. In this way, biological filter functions are preserved when the MechaniChem cartridge is replaced. A venturi air valve mixes oxygen with filtered water to improve gas exchange.