to elaborate on what i wrote, the bottom would probably need to be replaced, hence taking it apart. tempered glass has an 80% chance of not making it. there is a possiblility of the sheet making it, even though you might have a better chance of winning the lottery. i did a tank a couple years ago with tempered glass and the shop didnt want to do it since the probablity of breakage was so hi, but it turned out for the good. if the bottom pane is replaced, the glass can be tempered after drilling. your local glass shop can do it. | 
