What's in your pony?

[Randy g]

I will be diving with a 40cf pony this season, for the first time. I have spoken to several people with different ideas of what should be in the pony, some say air, some say nitrox. What say you?

Most dives are in the 80-120 foot range along the mid atlantic. In my mind, if the pony is used something drastic happed to my buddy or myself and the dive terminated.

TIA

 

[M_Bipartitus]

Air works well.

 

[Rainer]

I have no interest in using a pony bottle, but if I did, I'd put air in it.

It's cheap (which means there is little economic barrier to frequent practicing), readily available, good to whatever depths you plan to hit (and probably deeper), and gives no real decompression penalty if used only as bailout.

 

[merxlin]

Pony chow?

Seriously, I keep air in mine for the above reasons- easy, cheap, ability to use at any depth.

 

[idocsteve]

I just opened my pony and looked inside.

I didn't see anything

 

[SkimFisher]

Hay...

 

[Sas]

I've used air, mainly. Even if I am diving with nitrox. I just do another deco schedule for if I have to switch at depth to air (usually it's not much extra given the type of diving I do).

 

[Puffer Fish]

I would suggest something at or higher than the highest Nitrox you would use. If that is air, then put air in it.

If you don't, and whatever emergency required it's use, also requires any additional bottom time or you are near, close to, slightly over the no deco limit...and you don't have a multigas computer...set to what is in the pony bottle..you can do what Saspotato does...but if you want to do another dive (funny how it is difficult to really plan emergencies)..then you are hosed.

The result of having Nitrox is that the DCS concern is reduced, and replaced by a potential CNS issue... so one wants to choose wisely.

 

[Rainer]

Having nitrox (O2 significantly greater than 21%) in the pony has many downsides: cost (which is likely going to be a factor in how often one practices with the pony), availability, MOD limits (which might need to be violated in the very scenario in which the pony is actually needed), and (yes, limited) increased O2 toxicity potential.

The idea that bailing out to air from a nitrox backgas and making an immediate ascent is somehow going to lead to DCS issues is rather laughable.

 

[idocsteve]

I would suggest something at or higher than the highest Nitrox you would use.

Ok this sounds wrong to me, and I hope that someone can correct me before I some day fill my Pony bottle with Nitrox but here's how I figure it.

You've determined that you're diving at a MOD to which EAN32 is the safest gas to use, whatever depth that might be.

You have an OOA emergency at depth, you switch to the pony, which has been filled with EAN36, you spend some time at that depth figuring it all out, and WHAMO, you get an O2 Toxicity hit because the Nitrox in your Pony is not adequate for that depth.

What am I missing here?