One other more "permanent" suggestion to add to the others....we just use aluminum tanks here, so I don't know if there'd be any difference with steel....you could put your initials or whatever on the tank with one of those metal stamps...a die set, I think it's called? That's what I have on my tanks, along with painting...if your paint job is similar to someone else's (if you paint them at all) having your initials on the tank would eliminate uncertainty....and since the hydro info & serial numbers, etc are already stamped on the tank, it wouldn't cause any harm to the tank.