here is a great way to fix that. what i do for people all the time. this is permanent and chemical free solution for any center brace. i took 1/4 inch plexi glass. a pop rivet gun and a drill with the 1/4 drill bit the same size as the rivet. check your rivet size to be sure the bit is the same. drill at least four holes preferably 8. near the glass on both sides about an inch or so in. and then on either side of the break in the brace. as the holes are drilled put the rivets in or the holes wont stay lined up. use washers on both sides for extra security and also you can put the plexi glass on the bottom side of the trim so it isn't visible. if the rivets bug you you can paint them with black nail polish. eliminates all bowing in the glass and makes it more sturdy than before.
these new tanks are made of very thin glass. the older ones really didn't need the brace as much but they were made much better. i don't know how old/thick your tank is but because of that i would not trust it with the bow. you can keep the fish in the tank if you take the water level down untill about halfway and that will make it safer. also if you are careful not to get the plastic shavings in the tank from the drill you can repair a brace with the fish still in it. but you have to lower the water level more than 60% to eliminate the bow in the tank. possibly more. enough to where the center brace is touching where it was broken. i used a cookie sheet propped up on tank decorations to catch the shavings.
besides, you know you want to keep the 55 and still get the 125. lol
these new tanks are made of very thin glass. the older ones really didn't need the brace as much but they were made much better. i don't know how old/thick your tank is but because of that i would not trust it with the bow. you can keep the fish in the tank if you take the water level down untill about halfway and that will make it safer. also if you are careful not to get the plastic shavings in the tank from the drill you can repair a brace with the fish still in it. but you have to lower the water level more than 60% to eliminate the bow in the tank. possibly more. enough to where the center brace is touching where it was broken. i used a cookie sheet propped up on tank decorations to catch the shavings.
besides, you know you want to keep the 55 and still get the 125. lol