Hang On Back (HOB) aquarium filters use a very simple and effective design that is perfect for freshwater aquarium filtration. HOB filters are most commonly used on smaller tanks that cannot have a sump added or temporary tanks like quarantine or hospital tanks. HOB filters will also add flow to your tank encouraging gas exchange and helping suspend detritus for removal. They also use a secondary biological filter media that allows passive water contact for nitrifying bacterial growth and encouraging biological filtration functions.
HOB filters use filter cartridges that mechanically filter water through a pad of double thick poly-fiber, trapping debris and waste particles before the water is chemically filtered through Carbon. These filter cartridges are design to last 2-4 weeks and replaced during each aquarium cleaning.