Bonta: Yes, the sump came configured with a chamber (split vertically) where you can put filter media, live rock rubble, etc., then it goes into the skimmer area, then the refugium, then the return. Lots of baffles and I'm not getting any microbubbles in the tank at all. I'm going to put some live sand, live rock and cheato from my current tank in the refugium once I get the water at the right temp and SpGr.
I have the lights on the tank now and I am mesmerized by the shimmer! I've never had a metal halide before and it is so beautiful. The ceiling of the room and the wall behind the tank looks like I'm at an indoor pool with the light reflecting off the water.