So long as the skimmer isn't dumping enough microbubbles that the return pump is shooting them back to the tank they can reside together, ours is running like that now. Only difference is that we have a drain from the tank going to each the fuge and the sump, at least it will be that way by Friday, right now a single drain to the sump with another pump moving water to the fuge. We had a whole thread of sump/fuge pics around here somewhere let me dig it up.

Pretty open for debate as far as 'right' I guess the question is; is it working for you?

Here's the thread; http://www.captivereefing.com/viewtopic.php?t=554