What is your question??
a sum-p with no refugium is super simple to set up. The mag 7 should be fine for that skimmer, although if you havent bought it yet I would recommend a 12 actually. You can simply put a ball valve on it to taper it back accordingly, and you could put a T off of it with a ballvalve to run your UV so you wouldnt need an extra pump. You copuld also run a simple
canister filter for carbon or phosphate media off of the same return pump. I dont run either but I DO have a
phosban reactor set up to run carbon in the event that I want/need to use it. All i have to do is fill it up with carbon and open the ball valve and its good to go.
You want 1.5" in between each baffle, and 1.5" under your "under" baffle. This will give the bubbles all the time in the world to rise and for the baffles to do their job.
I would recommend you baffle configuration to be Over/under/over, with the baffle next to the skimmer section being at least an inch taller than the last baffle. This will make sure the water level never changes in the skimmer section so the skimmers performance NEVER varies in concern to the water fluctuating due to evaporation with or without an ATO. Im not sure of the perfect water height for your BM 200. I run my BM 250 in 7" of water, but my skimmer section actually operates with 13" of water depoth and I built a lift for the skimmer to have it at 7.
hope that helps and if it didnt......let me know what your question was.
