The only reason the run a skimmer in viniger is to thoughly clean it. A clean skimmer usually increases production although cleaning in viniger is not really needed. I get more skimate after cleaning my cup and neck. Cleaning the Venturi can also help a lot as it can get salt built up in it. This can easily be done by sucking hot RO/DI water into the air line. Clean the needle wheel as it can get debris in it. The pump body and rotor benefit from cleaning in viniger every 6 months to remove Calcium build up. Cleaning the pump can be the diferance between it lasting 2 years and it lasting 10 years. If the rotor magnet is swollen or distorted it should be replaced before it destroys the pump body.