Abstract: A filtration apparatus characterized by efficiency of the precoating step and maintenance of filtration performance over a long period of time after precoating has been completed. The filter promotes parallel flow of porous precoat material along a porous septum, thereby achieving efficient stacking of this material against the septum. A dual-speed pumping system transmits the precoat material to the septum at high velocity, thereby further encouraging efficient stacking, but pumps the fluid to be filtered at a lower velocity to minimize energy consumption.