240 gallon glass cages tank

Matt Nelsen has a pretty good take on this. I've talked with him at length about Glass Cages. You can find all kinds of people who rip on them for failed tanks, but the reality of it is that they make thousands and thousands of tanks a year, they have made most of the ones that Blank Park Zoo has IIRC, and if you count up the failure threads you find on their tanks, the rate is extremely low compared with the quantity they produce. On top of that, most of the problems with tanks/seams going bad can be directly attributed to the stand. If you take a glass tank with no rim and put it on a surface that is not perfectly flat and level or not on foam, it's likely to have problems.

Seams with bubbles, yeah, but so does the Miracles tank I had made. it's from gas within the silicone and it's extremely difficult to make a 100% perfect bubble-free silicone seam so those alone are not an issue.

So bottom line is check all the seams, look for stress bubbles (which are different, they will be thin and elongated, and you can look at my tank if you want to see what those look like /DesktopModules/ActiveForums/themes/_default//emoticons/smile.gif ) and like mentioned look for discoloration of seams. Also take a very close look at the stand, as long as the tank was sitting properly, it shouldn't be an issue. It might be worth considering that you want to "replicate" the conditions, that is, use the same stand and make sure it's sitting in the same orientation or something, etc, just so that you don't cause the tank stresses to "shift". I don't know if that it clear or not, or even if it matters, but just spouting off the top of my brain here.