Question Downsides of hydro testing more often than 5 years?

[Tracy]

One question. Where do you fit all of those annual hydro stamps on the tanks? Eventually the crown of the tank will be full! I have some tanks that would be going on 20 stamps now, and some divers have steel tanks way older than that!

I have bank bottles with full crowns. They attach a brass tag to the valve and continue the stamping.
Technically after 100 years of testing, you are stamping the same thing that is already on the neck.

 

[Bert van den Berg]

I have one tank due for hydro now, and another due in 3 years. It simplifies things if both tanks have the same hydro date since they're in doubles.

What are the downsides of doing a hydro test more often than every 5 years?

Seems strange that so many countries have different scuba tank hydro testing requirements. New Zealand requires a hydro test every two years and a visual between hydro tests. Australia apparently requires annual hydro tests and the USA once every five years?

 

[Angelo Farina]

I suppose you could argue stress on the tank (they do over-pressurize) but that seems pretty trivial given what you're planning. It's not like you're doing it once a year, every year. And even then, I'm not sure it's a big deal. Getting a hot fill such that the tank is at rated pressure when it cools and doing that twice a week is probably worse, but I'm still doing it....

Didn't Australia (or maybe somewhere else?) go to requiring annual hydros for a bit, then backed off? I assume they backed off because the industry and divers complained more about cost and hassle than stress on the tank.

In Italy hydro is after 4 years for new tanks, then every 2 years. We do not have annual VIP, indeed.
Twin tanks are usually tested together.

 

[ScubaBunga]

Shops will refuse to fill old (pre-1990something) aluminium cylinders because of the dodgy alloy used in some. At some point that was “ten years ago”. Don’t think there’s an issue with steel cylinders

Yeah that was 86-87, so a bit more than 10 years. Just ignorance to manufactures specs and tank lifespans. But I doubt I will ever own tanks there so not on my worry list.