Great advice, Erik.

If size isn't all that important, you should be able to pick up a used sump by watching for a few days. If it is important, as Erik said, get Ace (aka Hobogato) to throw one together for you.

Others really like the Koralias, I'm fond of my Seios - which are cheaper, but the entire unit has to stay in the tank.

As Erik says, don't overdrive your overflows. Make SURE you have enough drain capacity that if a snail or something else gets caught in one of your drains, your other drain(s) can handle the flow. You can also minimize your sump return section so that it can't overflow your tank.