So the center brace of my son's aquarium broke. I know there are some other fixes out there, but I just went with replacing the top rim. There are a lot of how-to's on the interwebs as well, but I never found one with pics, so I thought I'd share. It was a success. It took about 2 hours to get the rim off.
Picture of it before I ripped off the rim with a clamp on it so it wouldn't bow out
Then drain the water over halfway to take the clamp off.
The broken center brace
After using a paint scraper under the rim to loosen it, I started to just pull it off (carefully so the glass doesn't break
Two hours later....
Used a blade to get the silicone that stayed behind
After all the silicone is off, started to put new silicone on the inside of the new rim (and you can see the pieces of the old rim all torn off next to me)
Put the new one on, fill it back up...
Good as new with a happy kid!
All in all it wasn't that hard...the hardest part is not shown in pictures..Being careful not to break the glass when pulling off the top rim.
Hope this was a little informative and shows it can be done by someone with very little handy-man skills :-)