Thanks, this discussion is very informative which will help me in learning how to best use my new “alternative air” tank.
Not to hijack my own thread but build on it. When I sling the 40cf it’s usage can have different designations as I’m hearing. They are: (1) an alternative air source; (2) as a stage bottle; (3) as a deco bottle (4) others?
For each designated usage, what are their specific associated regulator configurations that are typical or expected? For example, one recommendation was to remove my second from my primary tank and use the pony bottle regulator as the second. Would this be for only the (emergency) alternative air source designation?
Somewhere, I read that if a charter boat captain/dive master hears that on a just completed dive you used your “pony bottle” just for extra air, he won’t be allow it. If true, what is the reason or justification for this complaint, and when would it be acceptable to use pony bottle air for the intended purpose of extending your dive?
It should only be the first three, alternate air, bottom stage, or deco bottle
For me the rigging would be identical for all 3, but regulator would be slightly different
Configuration would all be the same-ish for me. SPG, drysuit length inflator hose, 40" regulator hose likely with a ball swivel. If using for an AAS then it should IMO replace the short hose on your backgas and would have a necklace on it similar to left side sidemount bottle.
The "ish" clarificatoins
If used as an AAS or deco bottle, I would have no issue replacing the SPG with a button gauge since they're $15 instead of $70 for a real SPG and hose. It also removes the 2 most irritating o-rings in a regulator assembly on the spool, and the most leak prone hose. Having 100psi resolution on a deco bottle or pony is not required and the 500psi resolution on the button gauges is more than good enough. Hell for a bottom stage in OW it really isn't required either, though it makes checking a PITA so I'd recommend you use a real SPG if using it for a bottom stage.
Drysuit hose is not "traditional" and the DIR types don't like them. They also don't believe in pony bottles, so you're already out with that, but I have them on all of my stage/deco bottles. They're useful for CCR, but also for DSMB/lift bag use.
Hose length can be personal depending on if you use a swivel first stage or not and if you actually use the swivel if you do *typically not "Swiveled" when deployed if you have the drysuit hose on there*
Swivel would be a requirement for me if it is being used as a pony bottle for comfort, but not for a bottom stage or deco bottle since those do not live on your neck when not being used.
If you are using it as a pony all the time, then I would ditch the short hose on your backgas and use this like a left side sidemount bottle. If you are using it intermittently, then I would treat it like a bottom stage where in an emergency you go to your short hose first, then switch to the spare bottle.
As far as captains/dive masters, they can be weird, so I wouldn't plan on using it as a rule.
