Just a comment - I bought 2 29 gal tanks from Petco about 5 years ago. They were full of water the entire time. Within the past 6 months, both developed a major leak.
Maybe I got the two lemons in the barrel - don't know, only bought the two. But when i compare it to my Petsmart 75 gallon and 65 gallon (20 years old, left dry in the basement for a couple of years, still holding water with no leaks), seems like you may be getting what you pay for....then again, maybe not.