-stage filtration process ensures optimal living conditions for the aquatic life in your fish tank. The first two stages use porous foam and dense polyester for mechanical filtration. Then the activated carbon insert gets rid of chemical impurities. Next, the water flows through a Bio-Screen for removing any remaining debris. The final stage consists of C-Nodes that promote the growth of beneficial bacteria that remove ammonia and nitrites. It can be installed on the back of a tank with a clip and is easy to maintain. There are three variants of the Fluval C Power Filter available that will suit up to 30-gallon, 50-gallon, and 70-gallon aquariums respectively.
8. MarineLand Penguin 200 BIO-Wheel Power Filter

When it comes to the best hang-on-back (HOB) filters, MarineLand Penguin 200 BIO-Wheel Power Filter is a great product. It provides three-stage filtration for removing mechanical, chemical, and biological impurities in the water. Your fish tank will be free from waste, odors, and discoloration. Its Bio-Wheel is specifically designed to tackle ammonia and nitrites in the water while promoting the growth of beneficial bacteria. This model has a flow rate of 200GPH and will be suitable for 30 to 50-gallon aquariums. MarineLand Penguin BIO-Wheel Power Filters are also available in smaller and large capacities.
9. AquaTop PF40-UV Power Filter (HOB) with UV Sterilization

AquaTop PF40-UV is a versatile product among the best hang-on-back (hob) filters. It has a 7-Watt UV bulb in addition to mechanical and chemical filtration media for keeping your fish tank clean and healthy. The bulb gets rid of free-floating algae and parasites. There is a self-adjusting skimmer in the unit as well for cleaning the surface of the water. The filter uses a 7-Watt pump that has a flow rate of 128GPH. It will be able to filter water efficiently in 15 to 40-gallon aquariums. A knob allows you to adjust the flow rate as required. You can use AquaTop PF40-UV Power Filter in freshwater and marine setups. Smaller variants of this HOB filter are also available.
10. Aqua-Tech Power Aquarium Filter w/ 3-Step Filtration

Aqua-Tech Power Filter is a popular choice of the buyers who are looking for the best hang-on-back (hob) filters. It uses a 3-stage filtration process for keeping aquariums clean. The filter comes with coarse floss for mechanical filtration, activated carbon to get rid of odors and discoloration, and Bio-Tech Biological Grid for eliminating ammonia and nitrites. It is easy to install and maintain thanks to its HOB design. Aqua-Tech Power Filters are available in four different sizes that will be suitable for 5 to 15-gallon, 10 to 20-gallon, 20 to 40-gallon, and 30 to 60-gallon aquariums respectively.