Basically one of the front corners has a leak (i.e. it's not a break in the glass, it's that the silicone isn't holding the glass pieces together) so the front was starting to come loose and "push off" on one side - was getting worse quickly before I drained it.
The only reason I'm asking is because (hope this isn't too much info) I have been laid off for three months and spending even $20 on another aquarium stresses me out right now - also I have a 30g-high so if I found a standard 29g that would mean also buying a new top, new light bulb, etc...
And I DO have half a tube of aquarium silicone from an old misadventure, but I've never used it to build or repair an aquarium, and the biggest nightmare of all would be to botch the job and have the whole thing burst one night, flooding the apartment downstairs with water, which would probably get me evicted.
But you're probably right, I should just keep my eyes peeled for a deal on craiglist.