What is safe? Valve has 3000 psi rating, tank is faber HP 3180+

[ChrisA]

In fact, I even showed the guy at the dive shop. Hey, the valve has this 3000psi sticker on it, and my tank's supposed to be 3180+ (3500), and he said not to worry (what I wrote in my last post). Is changing a burst disc hard?

He's right it _will_ work. But then so does under inflating you car's tires or putting the wrong grade of oil in the engne and you really _can_ hold your beath under water (as long as you dont acend) and nothing bad will hapen if you come back to the boat with only 200psi not the 500 recommended. I even know of a guy who dives solo and breaths his tank to zero, then swithces to a pony

But there is a difference between "will it work: and "is it a good idea"

In theory the bust disk on a 3000psi valve will not burt if the tank is filled to 3500 but you have eaten into the built-in saftey margin