Caveat emptor. Sorry to hear about the experience. This probably won't be a very popular opinion, but it does sound like the seller is standing by the word of the agreement and you didn't go into the sale educated and prepared. He may not have disclosed important information about the tanks to you, but at the same time that important information is publicly available and, for instance would have easily come out if one had asked a question about the tanks here on SB. Chalk it up to one of the downsides of buying used equipment from unfamiliar sources (as you clearly already have done).
I don't think many people here (myself included) would be capable of making a sale like that without disclosing the 6351 alloy fact, but again the concerns about that alloy are dealt with on a per-shop basis, and technically your beef should be with a shop that refuses to fill such a tank that has passed hydro and VIP testing.
I don't think many people here (myself included) would be capable of making a sale like that without disclosing the 6351 alloy fact, but again the concerns about that alloy are dealt with on a per-shop basis, and technically your beef should be with a shop that refuses to fill such a tank that has passed hydro and VIP testing.