Earler this week in the middle of the knight the bottom glass of the tank gave out. Would it be worth fixing if so what kind of glass should i use?
Did the whole bottom give way or do you just have a single crack? And have you determined the cause of the crack (uneven stand, pressure point)?
I recently had my 180 crack on the bottom plane, ran from front to back. Mine is in my garage, so I went with a slightly riskier remedy and patched over it with an 18" wide piece of 3/8" glass (cost me $25 for the piece of glass). Pulled out all of the silicone on the inside of the tank, and resealed it with the patch resting over the crack. It has been running for about a month now (3 weeks with fish in it), and *knock on wood* it's still running.
Should be noted that I don't have any plastic framing on the outside edge of the tank, the glass now rests on foam, which is on top of a 3/4" piece of treated plywood that's serves as the support.
If you lost the whole bottom, you would have to get a new piece of glass obviously.