As promised.. better late than never!
closed loop with OM 4-way inside stand
equipment closet plumbing in progress
The sump was made by Tenecor. They did a nice job, it is basic but will suffice. Waste water from the RO/DI will be used to flush the self cleaning head on its way to the drain (black pipe coming out of the wall). The total drain tank will be the reservoir for top off water, and also do double duty as a salt water mixing tank for semi-automated 10% water changes. Two Deltec FR509 reactors will be added to the shelf with the KM500 kalk stirrer and PF601 calcium reactor.
The return pump is hard to see, it is sitting behind the skimmer. The 1.5" outflow leads into a tee then is reduced to 1" for the primary tank return line. The branch of the tee supplies a secondary return line, passing through the Teco TR20 chiller (in the pantry on the other side of the wall) before going back to the tank. Another tee from this same branch will supply the fluidized reactors (sequentially phosphate then carbon) before going back to the sump. There are ball valves on each limb to adjust flow. I expect to throttle the Dart return pump down, although there is a lot of pipe and numerous fittings so head pressure will take care of some of the excess flow. I did use long sweeps instead of 90 Ells which should a bit.
There are two drains coming from the overflow. The primary drain is the gravity feed to the skimmer, which ideally gets 800gph. I kept plumbing at 1-1/2" to the inlet where it reduces to 1". There is a bypass line from the gravity drain to the sump which should keep any surging out of the skimmer. I put ball valves on both the bypass line and the skimmer line, with the later as close to the skimmer as possible, to allow fine tuning of the flow into the skimmer. The other overflow drain is basically an emergency drain and empties directly into the sump. Normally I expect this to be closed, or nearly closed, with the ball valve. It is mainly there in case I need to take the skimmer drain of line.
To answer a previous question, there is black vinyl on the back of the tank only. I do need to do something with the sides. At this point I am undecided between painting them black, trying to apply vinyl (difficult now that the tank is in the niche), and using foam on the interior which will eventually cover with coralline.
Hopefully water testing will begin in the next 1-2 weeks.