Selection of a mechanical skimmer is based upon sump or tank factors such as: Access to the area where oils naturally collect (mount location of the skimmer)Reach needed to the lowest fluid level (distance from mounting point)Required rate of oil pickup (quarts or gallons per hour)Temperature of the solution (as in wash water) If using a mechanical skimmer, we recommend the use of the Diverter accessory, which mounts below the skimmer to redirect any removed coolant back to the sump or tank. See the Diverter section for details. If the sump runs only one or two shifts, then we also recommend the use of an Oxygenator during the time the pump is down. It will help to prevent bacterial rancidity by keeping oxygen in the fluid. See the Oxygenator section for details.