An apparatus may include a slotted filter that is generally circular in shape and positionable within a casing string. The slotted filter may include multiple filter chambers. Each of the multiple filter chambers may include a rear wall; side walls that intersect the rear wall; slots in the rear wall and the side walls; a bottom surface; and an open end positionable proximate to a centrifuge in the casing string for receiving a fluid containing debris particles collected by the centrifuge.