Best Air Mix for Pony Bottle

[WorkNPlayScuba]

Hello

I just wanted to get some opinions on EAN mixture choices for diving with a pony. My normal dives range from 30 to 60 feet and rarely exceed 70. I am considering purchasing a pony bottle for added safety. I was curious on what would be the best air mix for the pony bottle. I even considered filling to a mix of EAN50. I figured if something catastrophic happened where I had to transition to the the pony. I would hopefully be making a controlled emergency acend. The idea is that using a high EAN mixture would help off gas nitrogen while proving the air needed to complete the safety stop. According to a best air mix calculation, diving with EAN50, though above recreational mixture, has a maximum operating depth of 60 feet. Which would not pose an issue if I started acending during an emergency. I just want another opinion or someone second guessing my thought process to make sure I’m not doing anything out of the norm. Thanks for your posts! Safe diving!

 

[grf88]

It is a bailout why not just use air. If you do choose a nitrox mix make sure that it is suitable for your maximum hard bottom.

 

[DogDiver]

Pony should be filled with the same gas mix as your back mount.

 

[CuzzA]

Pony should be filled with the same gas mix as your back mount.

You're going to dump the contents every time you change your mix? Why not just fill it with air and forget about it. That's what I do.

 

[WorkNPlayScuba]

I just figured that maybe the benifit of breathing a higher mixture of oxygen could help reduce the nitrogen load during a quick acent, if it ever came to that.

It is a bailout why not just use air. If you do choose a nitrox mix make sure that it is suitable for your maximum hard bottom.

just

 

[Jonny Wishbone]

Hello and welcome. It depends . First off to fill a tank with EAN 50 , the tank needs to be 02 cleaned along with the valve. Then you will need to have whatever regulator you are putting on it 02 cleaned as well. Then there is the hit or miss rule that some dive shops have that they will not fill you with anything over EAN 40 without a Tech diving certification. (my LDS has a sign at their fill station on this) You can put EAN 40 in it without any cleaning provided they have a membrane system but most membrain systems are set up for EAN 32. If your fill station does partial pressure fills you are back to 02 cleaning even for EAN 32. Some people just put air in the pony on dives where if something is dropped, they can switch to air and go deeper than the MOD and retrieve the item and then switch back to their EAN when they return back above their MOD for the mix they are using.

 

[DogDiver]

Let’s not forget if you have different gas mixes you are now mixed gas diving. Conciderable training involved.

 

[grf88]

Pony should be filled with the same gas mix as your back mount.

Why?

 

[Jonny Wishbone]

You are right in thinking of lets say switching to EAN 40 for your safety stops.Its just added safety.. you never know if you have a body that will not agree with your dive profile and what your computer says you can do. If you dont mind spending the extra money to do it then you cant go wrong with an added safety procedure....

 

[grf88]

I just figured that maybe the benifit of breathing a higher mixture of oxygen could help reduce the nitrogen load during a quick acent, if it ever came to that.

just

Use a pony that will allow you to make an unhurried ascent.