What to fill a pony bottle with?

[deadly_risk]

I have been picking things I do not know anything about and reading over the related topics in these forums. I have seen allot of pony vs. no-pony + good buddy and off vs. on debates with good points to all sides.

I have not seen anyone talk about what you fill a pony with. It would make sense to me, on an average recreational dive profile to fill with EAN32 as opposed to plain air or even EAN36 if you are in a situation where you do not spend time below 94 feet or so (maybe a hard bottom at 85' at your quarry or whatever). Am I guessing right here? I don't use a pony and am asking just to know.

My reasoning would be if you switch to the pony the dive is over and you will be making an ascent, possibly more quickly than average, and maybe forgetting the safety stop. The higher FO2 would increase the rate you off gas absorbed nitrogen and the resulting nitrogen bubbles would be smaller than if you were breathing air.

True? Not True? Beats me.

 

[dumpsterDiver]

Fill it with air. You don't have to clean the bottle and if you ever exceed the MOD of your nitrox mix and begin to feel "bad", you might prefer to have air to bail to.

That is generally what I do, anyway. The issue with decompression etc. is probably a very minor issue.

 

[DevonDiver]

I concur that adding Nitrox to the pony makes a lot of sense. Within recreational depths, a mixture of 32% is easy to obtain and provides a back-up gas source within MoD anywhere above 32m. If you were below that depth (32-40m) and needed to access your gas, you only need to do ascend a few meters before it would be safe to utilise at ppO2 1.4 (although you would probably get away with using 32% at 1.6 ppO2 immediately, as it would only be a few seconds before you were above the MoD anyway).

The other benefit of using Nitrox as a contingency gas, is that it would add a slightly larger safety margin in the even that you had to use it to complete emergency decompression.

 

[scubaren]

ponies?

 

[LowVizWiz]

Fill it with air. You don't have to clean the bottle and if you ever exceed the MOD of your nitrox mix and begin to feel "bad", you might prefer to have air to bail to.

That is generally what I do, anyway. The issue with decompression etc. is probably a very minor issue.

If you're talking strictly rec. NDLs I have to agree with filling it with air. Can be used at any rec. depth any time by you or someone else and can be filled or topped off by anyone too. I usually get topped off for free with just air.

 

[Web Monkey]

I have not seen anyone talk about what you fill a pony with. It would make sense to me, on an average recreational dive profile to fill with EAN32 as opposed to plain air or even EAN36 if you are in a situation where you do not spend time below 94 feet or so (maybe a hard bottom at 85' at your quarry or whatever). Am I guessing right here? I don't use a pony and am asking just to know.

Fill it with air.

The last thing you want when OOA is to wonder if the mix in your pony will kill you at your current depth.

Terry

 

[Doc]

Listen to all the above, but hear what isn't being said.

Tailor your "pony" mixture to the needs of your specific profile dive.

If you are concerned about needing an EAN tank one day and an Air tank on others, that's the price of admission then, isn't it?

It's not an ornament, it isn't "one size fits all".

Failsafe to Air.

 

[NorthWoodsDiver]

Air- simple, cheap, doesn't require special cleaning, MOD is like 218', doesn't require an additional cert to get a fill, etc.

 

[DandyDon]

Fill it with air. You don't have to clean the bottle and if you ever exceed the MOD of your nitrox mix and begin to feel "bad", you might prefer to have air to bail to.

That is generally what I do, anyway. The issue with decompression etc. is probably a very minor issue.

Yep.

And why do you think you're going to skip a SS? Even a 13 CF should give you enough for an ascent from any recreational depth I'd think, a 1 minute stop at 1/2 depth, and breath it out around 15 ft followed by turning the pony valve off to prevent water from backing in and a very easy CESA.

But for $10 more, same reg, spg, sling, get a 19 CF that weighs only 2# more with 50% more air.

 

[rmc77]

Ponies don't have that much gas to be worrying about MOD and such. Also, for the same reason, it won't matter if it's filled with air or EANxx... The time you'll be breathing from it is insignificant. So, why bother? Fill with air and you're done.
In the other hand, I would say your concept is right; EAN32 would be better for a recreational dive... My point is that a pony has so little gas that you would not benefit from that.

Cheers,


Rafael