Coming back here to carry on, although I've had a rough couple of weeks...
My magnifica continued to decline. As did a couple BTAs. As did several corals. I did numerous water changes, fed more, fed less, etc. But I lost them all, over a period of a few weeks. I've been really upset about it, which is why I haven't updated this thread in forever. In the end, I learned it was a combination of low nutrients and low pH. I had removed my protein skimmer a long time ago, and recently disconnected my frag tank to treat an algae outbreak. The loss of those two water circulation systems led to an average pH of 7.8, which I hadn't been checking.
After things stopped dying, I remodeled the rockwork, removed some of the RBTAs, and basically got a fresh start.
I am also still determined to keep magnificas, and, on the off chance I am dealing with too much allelopathy, I am starting up a second tank for that express purpose.
All told, it hasn't been all bad. I moved my Gigantea to the display. The clowns immediately took to it, but fortunately they have been gentle.
And my LTA has been doing fantastically, despite being hidden in a corner where I can't see it too well.
I'm hoping to start doing updates more frequently again. Here's hoping things are headed up from here. And I think I'll be the proud new owner of Colorado Sunburst soon, so that'll be a nice addition, assuming it plays well with my RBTAs and my Chicago.