When the contamination levels of system fluid are unacceptably high, in-line filters may provide only part of the solution. The addition of air breathers, suction strainers, and/or magnetic separators can help control the introduction of harmful contaminants in the system fluid. An air breather will effectively reduce the ingestion of airborn dirt particles when the fluid level drops within a reservoir.  The amount of debris introduced during the fluid replenishment process can be minimized with the use of a filler strainer.