I'm new to posting in the thread, but I've been reading along since around Christmas time(it took me a whole long while to catch up on the posts). I told myself I'd read the entire thread before posting anything, so I ended up forgetting most of what I had thought. You, however, just reminded me of a suggestion I have for the unit.
There must be flat end caps for the flowering units' fence posts. I haven't looked, but I'm sure they're out there. My suggestion is to use those on the draining side, with a pipe running from the bottom center of that cap, through an elbow, and straight down into the reservoir. Inside the fence post, you'd have to probably increase the pitch by a few degrees(which isnt really detrimental right?), and probably caulk(or some other filler?) the hell out of that side of the fencepost, to force all gravity-fed runoff into the pipe. Doing this would eliminate the need for an open flap. Wouldn't that give you better(total?) light blockage to your res/roots? Wouldn't it also drastically reduce the amount of waterfall noise?
Anyway, I thought at this point, with being such a quality thread, I had to toss out one idea for improvement.
Stinkbud... man, this thread is a really badass contribution to our society. Much props, and I can't wait to see you in HT.