Drained, as in oxydation and 2" of salt water still in the tank during a VIP. He told me has drained it before. He gets his main tank down to 200psi, switches to his pony for his safety stop, sucks it down to zero and then goes back on his main for the ascent. I was shocked to hear that from someone with a ton of dives. He also had to get his pony reg serviced after allowing salt water into the first stage while attached to an empty tank with the valve open.... they're refillable, you know ...
... Bob (Grateful Diver)