Have you considered building a skimmer that does not rely on a pump to pull int the air and pump the water.
You could build or mod a skimmer to be a counter current, air driven. You would be able to feed the skimmer directly from your over flow. All you would need to do is get your self a quality ceramic air stone, and a small Luft air pump.
IMO these type of skimmers give much better dwell time, bombbardment rate. With the correct air to water ratio you can out skim any skimmer on the market.