Yesterday I had a center brace failure on my 55g. The tank is relatively old (I bought it used 3 yrs ago) and has had intense lighting (2x96 watts PC
) for 4-5 years that I know of. I did a water change and upon filling the tank back up the brace started breaking as I watched. I decided to drain the tank and move the fish to another tank temporarily, today I got a new 55 and everyone is back "home" after a lot of work. I'm sure most folks don't think to actually look at the braces on their tanks....certainly can't hurt to check them closely when you do a water change, particularly with an older tank or a tank with strong lighting. I was lucky that I heard the plastic snapping, had I not the outcome could have been much worse.