What is a Hang on Tank Filter?
A hang on tank or H.O.T. filter can provide mechanical, biological and chemical filtration in an aquarium. It is called a hang on tank filter because it hangs on the back wall of the aquarium, with the filter itself external to the tank. An intake tube extends inside the aquarium pulling water into the body of the filter, where it passes through various mediums before being returned to the tank. A common hang on tank filter consists of a plastic rectangular compartment segmented by an insert in which a filter bag is kept. A small magnetic driven impeller motor pulls water into the filter where it first passes through a foam pad. This removes large debris like uneaten food, waste, or bits of plant matter, thereby providing mechanical filtration. Next the water passes through a filter bag that normally holds activated carbon. Activated carbon pulls organic pollutants from the water, further purifying it. This provides chemical filtration. Finally, carbon and the foam pads provide a home
