Fill pony bottle from main tank?????

[danceswithoctopus]

So you're hitting the dive site with a pony that's not full? Why? Most LDS's around here will top off the pony for nothing, especially if you leave money there often (fills, vips, hydros, gear). So you're loosing a little gas when you test the reg and when you take it off, but that takes a while to become any significant amount. So are you using the pony underwater while there's more pressure in your main tank?

I don't get it.

 

[sheck33]

i am good, i am good and i'll shut up before i say something :baby:

 

[BEM]

AWAP gave me a good idea on keeping a pony filled after loosing air to charging the reg and testing pressure. He suggested running a HP hose from my 1st stage (main tank) to the 1st stage on the pony (13 cu.ft.)

Could the more knowledgeable members comment on:

1. feasibility, wear and tear on the 1st stages due to removing a HP plug, installing the crossover hose, filling, removing the hose and then replacing the plug.
2. main tank is Nitrox (< 40% O2) and pony is not O2 cleaned. Any possible issues and problems topping off the pony with O2 mixes between 21 and 40%?
3. any regulations (Canada or US) on having to identify the pony (NITROX band) as having a > 21% O2 fill?