Originally Posted by ScaryFatKidGT
125g's usually have 2 braces making the tank 3 sections.
Some of the older tanks used 1/2" glass and were only braced in the middle or not at all. Now they use thinner glass and more bracing. They don't make them like they used to.
Originally Posted by newtot
It's a 6ft 125 gallon. I don't think it ever had a glass center brace. But the plastic brace attached to the frame is gone.Attachment 248175
I am pretty far from an expert in this area but what I have seen people do in the past is add a piece of glass as brace. Then use silicon to connect it to the glass of the tank. Some tanks are actually constructed this way to begin with. If you try googling <glass center brace aquarium> you should find some tutorials.
You could also eurobrace the tank which involves removing the frame putting a layer of glass all around the top edge.
Lastly, I don't know if a 6ft 125g tank made of 1/2" thick glass needs a center brace. You could find an engineering type to figure that out for you.