Update, 6/18/22
My first major BS event in the hobby: the bottom seal on this tank decided to almost, but not quite, give up the ghost. Through a minor miracle no water leaked, but it did leave me scrambling to find a replacement. Fortunately,
@Blaise006 had a spare RSR250 that I was able to swap in, so all I had to do was drain tank, remove rockwork, catch fish, swap tanks, then reverse the first three steps. I lost one of the two recovering heads of HG torch, as well as a recovering head of aussie gold.
This transfer led to my second major BS event in the hobby. As best I can tell, the stress of the move kicked off (what I believe to be) a velvet outbreak in the tank. I noticed something was amiss a little over a week ago, kept an eye on it, and it proceeded to very quickly affect everything in the tank (with the notable exception, so far at least, of the melanurus wrasse and the watchman goby.
I'd initially intended to wait until next week, when I transfer the rock into a new 4' tank, but over the past 36 hours I've lost all four of the vanderbilt chromis and one of the lyretail anthias. I've now been equipped for QT thanks, again, to Blaise006 and a lot of loaner equipment, and my wife and I were able to catch the mandarin, squaretail tang, and slowly-turning-male lyretail anthias tonight and get them into QT. We're going to try and catch the remaining fish tomorrow and get them started on QT as well.
This will definitely be informing my approach to quarantine going forward, especially as I graduate to larger tanks.