My steel tanks
- one old Swedish, galvanized, heavy (thick wall?) 10 y.o. no rust whatsoever,
- two Scottish reds, galvanized and painted, 5.y.o., well, not quite so good - getting rusty,
- one Spanish, new - no galvanization, just painted - we will see how good, so far so good, hopeless regulator
though - no thread, sort of 'push-on' solution,
The plastic bottle - all Swedes I asked recommend them. I have seen them available in the US. Probably my pick for replacement.