A pony should have just plain air.
If you pony is filled with air, you'll never be faced with the possibility of having to breathe Nitrox at a depth deeper than its MOD.
If you assume a pO2 max of 1.4, the MOD of air is 185 feet, which is significantly deeper than any recreational diver will find themselves (hopefully).
If your pony is filled with EAN32 and you find yourself at 140 feet (downdraft, emergency, etc.) in need of your pony, what do you do? Do you start breathing from your pony at 140 feet (pO2=1.7) or do you attempt to ascend to 111 feet (pO2=1.4) before breathing from it?
Do you really need to be making these decisions in an emergency?
Forget all that, just fill the pony with air. Any advice on filling the pony with Nitrox is bad advice. A pony with air is available to you at any depth. And if you are in need of your pony below 185 feet... well it's just a bad day for you.
If you pony is filled with air, you'll never be faced with the possibility of having to breathe Nitrox at a depth deeper than its MOD.
If you assume a pO2 max of 1.4, the MOD of air is 185 feet, which is significantly deeper than any recreational diver will find themselves (hopefully).
If your pony is filled with EAN32 and you find yourself at 140 feet (downdraft, emergency, etc.) in need of your pony, what do you do? Do you start breathing from your pony at 140 feet (pO2=1.7) or do you attempt to ascend to 111 feet (pO2=1.4) before breathing from it?
Do you really need to be making these decisions in an emergency?
Forget all that, just fill the pony with air. Any advice on filling the pony with Nitrox is bad advice. A pony with air is available to you at any depth. And if you are in need of your pony below 185 feet... well it's just a bad day for you.
