Abstract: A liquid filter device can filter liquid flowing therethrough using a granulated filter media included in a tank. The liquid filter device can perform a backwash of the granulated filter media by creating active zones and inactive zones in the tank. In the active zones, the granules are agitated and driven by a flow of liquid toward the top of the tank. In the inactive zones, the granules fall by gravity toward the bottom of the tank. The liquid filter device can include a conduit, a hub and a number of laterals, each of which may individual fit through an opening in the tank and be assembled to form a combined structure that will not fit through the opening in the tank. The active zones may be created above a top surface of each of the laterals by including slots on the top surface.