They will bsaically keep their plus rating forever. It is rare to have a tank pass test and not qualify for a plus. Not saying it doesn't happen, it does. It is just very rare.That's plenty for a single dive for me, but got me thinking about if I were to buy older tanks or keep new ones for a long time, if they'd likely lose their + rating at some point in the future and if so, how long if kept in good condition until they usually no longer earn it in hydro?
It comes down the person doing the testing. It has nothing to do with past testing. If it passes currently, it qualifies. I will say this warning, if the REE is not stamped on the tank, the odds of getting a plus stamp at test drop near 0%.Also, it I were to find some older tanks that were originally + rated, but hadn't received the stamp in the last cycle or two or something, would most shops have any issue trying to get the + rating back, or once they fail to stamp + is that it for future hydros/fills?
It isn't that the tank doesn't qualify, but almost nobody is going to dig out books of factory specs to look up what the REE should be.
Many older steel tanks did not have it stamped on them. Most from the last 20-25 years do.
In most places, it has nothing to do with the stamp and everything to do with the person holding the fill whip.The loss in gas capacity wouldn't necessarily be a deal-breaker for me, I would just prefer to know what I'm getting into beforehand since the rated volume seems to rely on this stamp.