If you have a large "final chamber", run 2 drains out of your tank, one into that one, and one into the first one. Make the center center chamber your return chamber. You can slow the flow on the "first" chamber, and use that as a refugium. Leave the skimmer chamber flow un restricted. It will also help because you skimmer chamber watr level will always be constant. That is a must. I have a 10 gallon tank made by one of the members here that is setup the same way.