An improved aquarium filtration system is provided which includes a
bio-reactor chamber. The bio-reactor chamber includes a plurality of
bio-balls which have a high surface area for collecting bacteria for
biological filtration. The bio-reactor includes one or more pumps for
pumping both water and air into the bio-reactor chamber. Preferably, the
oxygenated water creates protein laden foam and the bio-reactor chamber
includes a removable protein collector. To this end, the bio-reactor
chamber includes a vertical column for carrying the protein laden foam
into the removable collector.