No canopy, you're on your own sir. It does rust if I leave water on it and I believe some of the joints he welded have rust on them. In hindsight, I would have powder coated it or at least rhinolined or plastic dipped it.
I just got a welder that works with stainless steel to make me a trim around the top of the tank with 2 braces across. My tank didn't come with a center glass brace but resealing a 215-gallon warranted some additional bracing to help me sleep at night. I think total with labor and materials was about $200 for that thing. I found the guy on Craigslist but he's no longer there.
I used to keep mine on the sand and away from all other rocks. It'll overtake any area you put it on and smother other corals out.
It really doesn't need a ton of light so the sandbed is usually good in most tanks, unless you have dimmer lighting.
Nice John! They are alveoporas. While they look like flowerpot corals (gonipora), they are much easier to keep and aren't as temperamental as the goniopora. I've had mine for almost 3 years now and it's been a trooper. Pretty hard to kill... and believe me, I've put it through some tests!