To add to that. I presently have 9 tanks running all used. A few. Are as old as twenty plus years. To be perfectly clear I have resealed a few of them. But because they ever were leaking. Mostly just to freshen them up. Or because I was worried it may leak. But none ever have. The only thing about used tanks is scratches. You gotta look them overA total of all my tanks So far(10) have been bought used.never had a leak. Size 10 gal - the 90 that I have now.Maybee I'm lucky , not. The black cat under latter with a broken mirror, has better luck..... I just give them a good look over...