You're probably ok if you're not going to have the tank more than 1/3 full. I had a 55 AGA and the top center brace broke while the tank was full. The sides bowed out about 1/4 inch.
A few years back I worked at a LFS where the owner did the same thing. He cut the brace and put in a piece of clear plexiglass, so the light would shine through. I was there when he cut it, the tank was full of water, and there was a noticeable bow out. It didnt leak then and there, but I feel the integrity of the tank was compromised. I would not do it.
My sump is running around 2/3 full. No chance I'm doing it if i compromises the integrity with that much of a bow. I guess a inch and a half blackout band from my light won't be too bad...
the brace actually holds the sides in. I'm surprised but I've seen it myself. Bought a used 55 with a cracked brace. Filled it up with water and scared the heck out of myself!! you need the brace.
On the other hand one lfs replaced a broken brace with clear glass (about a 6" band) and it does not bow out.
