That is not.....going to hold.
Short of buying a new frame and replacing(a tough job), a U shaped brace, small, strong and discrete would be the best solution going front to back on the outside of the frame. The other option is to remove the top frame and eruo brace with 1/2 glass slats
I've repaired and removed all sorts of tank issues and been given free tanks like these for a long time, I've fixed each one, but.......they are PITA.
I could have worked PT at Burger King and made the difference for a nice new ADA tank for the same time and energy.