Thanks everybody for the feedback.
Wooddood: I'll definitely make sure to take a lot of pictures as I progress... the fun part is going to be the construction of the room. It'll be in an unfinished/uninsulated workshop, so we'll be doin' just about everything construction-wise.
mps9506: Our goal is to primarily grow out SPS, Zoas and some of the Orange-Tip Rose BTA's that are slowly overrunning our display tank.
But at this time we're pretty much open to anything (as long as it's not sinularia).
I also agree about the Mag pumps... they work great but dissipate a lot of heat into the water... I made the mistake of adding a Mag9.5 to my display tank (on the overbuilt skimmer) right before the summer hot season hit and I had a heckuva time keeping the tank temps down. The Mag5 I currently use as a sump return seems to not dissipate as much heat since it's half the wattage of the Mag9.5. I've also heard of people having trouble with the impellar cap seal when using Mags externally, so I opted to go for a 'real' external pump.
Pro_builder: I had thought about the possibility of building some DIY eductors on the closed loop system... they supposedly will take the flow up a few notches. What do you think? Either that, or I can do an eductor/SCWD combo if I decide to change-up the flow.
mwrager: Thanks... I'll have to get the wife over here to read your post... I need backup.
Cougra: Thank you also. I'll definitely keep this thread updated as I make progress.
I also found the source of the paint I need,
Aquatic Ecosystems
It's a 2-part epoxy paint, and costs about the same as good house paint... about $46.50 a gallon (of course it's hard to ignore the huge letters 'MSDS' on the page
). I figure I can get by with 2 gallons of the stuff, and figured I'd go with white so I get maximum reflectivity.
I also had another revelation... now that I'm going with an external pump, I can move the sump. It's going to go underneath both raceways on the floor, that way I open up the corner for other stuff. I previously had left that space open to add another raceway in the future, but figure it would be interesting to engineer should I go that route, being that it would be lower than the sump... if we go bigger we'll just have to build a bigger place to do it.
I'll draw up the revised plans and post them later on. The sump will also be the same size as the other two raceways, ~80 gallons.
This will also give me more room for the couple-hundred pounds of live rock that I'll eventually need in this beast.
Keep that feedback comin'.