Did you buy the tank new? All Glass Aquariums (assuming it is an all glass or a oceanic) has warranted there tanks for 7 years since at least 1996, maybe earlier than that. I would contact the manufacturer, and if possible get a new tank for free. If it is not warrantied I would reseal. Brfore you get too worked up, you need to find where it is leaking from. Is there any auxilary equipment that it could have been? Overflow maybe?
Oh yeah, since it was a reef that leaked, I'm moving it to the SW
general discussion forum, but I'll leave a shadow here, cause leaking tanks are available in both FW