external power filter: waterfall bio-filter had high efficiency biological filtration function, it draws water from the aquarium through the input assembly and into the input section. the water flows must pass through the double bio-sponge foam insert which strips most particulate matter from the passing flow and holds it.the flow diverter directs the flow beneath the filter chamber. the filtered water is forced through the entire foam insert active carbon, ceramic rings, filter sponge, bio-sponge to trap suspended particles and then to absorb liquefied waste.