Thanks Tony!

This is great; I'm getting the popcorn.

Sorry for the dumb question: I understand the closed circuit system with the Ocean Motions, but I don't see where the tank is connected to the sump and skimmer...

Nope not a dumb question, it's hard to tell and kinda not so normal.

Flow out to the sump is from the 15" weir, on the left of tank (facing tank viewing)

http://i232.photobucket.com/albums/e...sb4e91e07.jpeg

and you can sort of see whats going on here from a earlier picture.

http://i232.photobucket.com/albums/e...s9d70d721.jpeg

You might need a lot of popcorn and or starve like the last guy who waited in picture above if your expecting me to keep a steady stream of updates… I kinda wander off from things.

I can live on popcorn for a while...

And the return line (Sump to DT)?

http://i232.photobucket.com/albums/e...sabbd7359.jpeg

On the back wall are the closed loop feed/outtakes with the big strainers, they T into one.
The OM feeds the two rear inlets on the same cycle and the front two on the other cycle creating a spin action in the water, in theory. The sump return is up high on the right wall shooting across to the weir. It's plumped under bench, under tank and then up.

Hot air I hope?

Yes, people say I'm full of it...

Cool, so the sump return pump is different from the pump under the DT feeding directly into the OM.

Another dumb question: why is "closed loop" better than the traditional return pump from the sump system?

Correct two pumps, look back a few to mixing station pictures, you'll see the sump with a PVC line going straight up to the bench, thats a Waveline 12000.

Your closed loop would not be used for sump return, it wouldn't be a closed loop then. A closed loop is generally for flow and circulation in your tank with out having to add power heads or vortex style pumps to your DT. A CLS has no chance of back siphoning, and allows use of a low pressure-High Flow pump to provide increased flow and less power usage.