My advice is Be very careful when buying used, dont let your excitement get the better of you, it may be a good deal, but make sure you check those seals and top & bottom braces, do yourself a favor.
I bought a used 60 gal, and ignored some wear & tear on it, loaded the sucker up, bought sand, 60 gals SW and 3 days later the silicone gave, rear pane popped out and I had 60 gallons of saltwater in my apartment...thank god for Shop-vacs is all Im saying...
Bottom line, use your head & buy smart..