Continued thanks for the helpful feedback. I’ve seen people mention they dive with their pony rigs pressurized but closed. I’m wondering if this means they enter the water with the system pressurized then they close the pony tank valve until needed, to keep water from entering the 1st stage (which I'm guessing is what could happen if the pony valve is never opened after the reg is attached) and at the same time prevent free run from the 2nd? (Please advise if this is drifting OT and I will start a new thread.)