Helix Disc filters can be installed in any orientation; however, it is preferable to install them with the 3/4″ flush port at the bottom. As water enters the filter housing, a high velocity centrifugal action occurs, spiraling heavier particles (sediment, scale, etc.) away from the disc cartridge, down to the base of the filter. These accumulated particles are then flushed from the filter via the 3/4” flush port connection at the base of the filter (valve not included).