halocline
Contributor
The only reason to soak in a tub is to check for air leaks. A hose wash down will get as much or more salt off than any soaking.
I'm not sure if you've read this thread, or the one I started in the regulator forum, but all the evidence leads to the opposite conclusion. Exposed threads, hard-to-reach areas in the ambient chamber...
Regarding the so-called "dust caps" and the often-repeated statement that they don't keep water out because they are called "dust" caps, this is another bit of dive shop lore that's based on nothing. Of course the caps are intended to keep water out of the first stage, what else would they be for? Dust....come on. Maybe when you start diving in the desert you can worry about dust.
It's very easy to determine if your dust cap seals; simply install it and suck on a 2nd stage. No air? No water intrusion. If you do get air, it could still be a 2nd stage vacuum leak or a seat saver in the other 2nd stage. So in that case you'd want to investigate a little further; probably the easiest thing would be to remove the 2nd stage from the hose, and try sucking on the hose. It's pretty rare that a cap in any sort of decent condition won't provide a good seal.
But, for the ultra paranoid who really believe that a device designed for underwater use might be harmed by soaking in a tub, or for Atomic users, soaking pressurized is the way to go.