so what you are saying is, with a 90-110g tank and a 30f sump, id only be looking to run about 1.5 x that through my scimmer every hour? if the flow is so little...id consider putting the scimmer on its own closed loop at the back of the tank with a small motor to drive it and keeping the water level inside the sump identical to the water level of the tank.
And I am really interested in building most of this stuff, as its a nice way of saving money and also helps sway the wife...$300+ for a store bought scimmer, or 100 or less for my own...and with my own I know how it works, how to repair, everything.
This is the scimmer im going to make (with a little modification):
http://www.hawkfish.org/snailman/diy6inskimmer.htm
I plan on using a device called a bubble disk that is great at making an obscene amount of small bubbles and is about 5.5in across...fitting perfectly in the tube. The pump that powers it will also feed a couple of aerators in the refuge, as I am planning on displaying part of that tank too.
If only about 160g needs to get to this every hour, im going to figure out a way to get that out of the tank without adding a bunch of extra showing pipes in the tank.