Pony Bottle Regulator Setup

[samer0214]

Primary Tank - 1st stage, second stage, octo
Pony Bottle - 1st stage, octo

I'll normally put an appropriate nitrox mix in it, so that it can provide some off-gassing benefit in a stressed ascent.

I have never been trained on Nitrox, nor have I done any diving with it, but I like your idea of the Nitrox mix in the pony. Would it be OK for a recreational diver like me to, to adopt that idea (mine is only a 6 cu.ft. Bottle), and if so, what mix would you recommend?

Thanks - Samer

 

[chrpai]

I have never been trained on Nitrox, nor have I done any diving with it, but I like your idea of the Nitrox mix in the pony. Would it be OK for a recreational diver like me to, to adopt that idea (mine is only a 6 cu.ft. Bottle), and if so, what mix would you recommend?

No. You shouldn't breath any gas that you don't fully understand. The class is cheap and beneficial to recreational mid-range ( say 60'-110'ish) diving.

 

[Tortuga68]

Apart from MOD, what else is there to understand

 

[DevonDiver]

If you're trained on nitrox as a recreational diver, you can use >40%. I don't believe there's any stipulations on not using it in a pony. The mix would depend upon the depth of your dive and your personal preferences/strategy. If you don't have a personal strategy, my advice would be to stick to mixes within the MOD of the dive you're undertaking.

Back when I dived with a pony (I use sidemount now), I used to get it filled with 40%. That brings the MOD above the bottom depth of many of the dives I did - I had to partially ascend to make use of the mix (within rec MOD limits - 1.4ppO2). That's a compromise in efficiency. However, for me, the compromise was justified in that the richer nitrox mix offered some deco relevance should I over-stay/delay on my typical deep/square profile (wreck penetration) dive... and/or could be utilized for dedicated deco when planned as such (I am tech-trained).

If the pony is just there to get you to the surface in an OOA scenario, it's probably not worth juicing it with richer O2.

 

[nimoh]

If you're trained on nitrox as a recreational diver, you can use >40%. I don't believe there's any stipulations on not using it in a pony. The mix would depend upon the depth of your dive and your personal preferences/strategy. If you don't have a personal strategy, my advice would be to stick to mixes within the MOD of the dive you're undertaking.

Back when I dived with a pony (I use sidemount now), I used to get it filled with 40%. That brings the MOD above the bottom depth of many of the dives I did - I had to partially ascend to make use of the mix (within rec MOD limits - 1.4ppO2). That's a compromise in efficiency. However, for me, the compromise was justified in that the richer nitrox mix offered some deco relevance should I over-stay/delay on my typical deep/square profile (wreck penetration) dive... and/or could be utilized for dedicated deco when planned as such (I am tech-trained).

If the pony is just there to get you to the surface in an OOA scenario, it's probably not worth juicing it with richer O2.

I believe you meant to say <=40%, but also >=21%.

Andy, I don't have nearly the technical experience as you do, and so am in no position to criticize, but do you really recommend a recreational diver with no training in gas switching to take a mix past its MOD?

 

[samer0214]

DevonDiver: Thanks for the reply. You are correct in that the intent of the pony in my case is strictly for an OOA emergency, thus it's smallish size. The idea of the Nitrox in it was intriguing to me, no more. Perhaps I shouldn't bother as you suggested.

If I do decide to dive with Nitrox, I will take a class for it.

Thanks - Samer

 

[rhwestfall]

If the pony is just there to get you to the surface in an OOA scenario, it's probably not worth juicing it with richer O2.

Ding! Ding! Folks we have a winner!!!!

 

[DevonDiver]

I believe you meant to say <=40%, but also >=21%.

Typo... thanks.

....do you really recommend a recreational diver with no training in gas switching to take a mix past its MOD?

My advice is pretty clear, hopefully.

I think the nitrox course is (should be) ample training to understand the concept of an MOD.. and the principle of not breathing said gas below it. I did (try to) infer that to opt for that solution should be the result of a defined, researched and understood strategy. I probably didn't make that clear enough. To have such a strategy (as I intended to describe it) would mean being sufficiently informed to balance the potential risks and benefits. It would also mean undertaking dives/profiles relatively uncommon to novice/ general recreational divers. Realistically, this is advanced diving (not in the AOW sense..) bordering on a 'tecreational' approach.

In my case, I balanced the risk of incurring deco against the risk of limiting the depth applicable for my pony...and not having the pony for immediate use below that MOD.

Truth be told, I think that:

1) On a recreational dive, circa 30m/100ft...
2) With <=40%...
3) Given the short duration breathing a pony, for ascent only...
4) With an informed knowledge of PPO2 limits beyond only one agency's recommendations...
5) Understanding the link between CNS, PPO2 and time...

... well, you can guess what my thoughts were about use of said mix in a real emergency...

 

[nimoh]

Typo... thanks.



My advice is pretty clear, hopefully.

I think the nitrox course is (should be) ample training to understand the concept of an MOD.. and the principle of not breathing said gas below it. I did (try to) infer that to opt for that solution should be the result of a defined, researched and understood strategy. I probably didn't make that clear enough. To have such a strategy (as I intended to describe it) would mean being sufficiently informed to balance the potential risks and benefits. It would also mean undertaking dives/profiles relatively uncommon to novice/ general recreational divers. Realistically, this is advanced diving (not in the AOW sense..) bordering on a 'tecreational' approach.

In my case, I balanced the risk of incurring deco against the risk of limiting the depth applicable for my pony...and not having the pony for immediate use below that MOD.

Truth be told, I think that:

1) On a recreational dive, circa 30m/100ft...
2) With <=40%...
3) Given the short duration breathing a pony, for ascent only...
4) With an informed knowledge of PPO2 limits beyond only one agency's recommendations...
5) Understanding the link between CNS, PPO2 and time...

... well, you can guess what my thoughts were about use of said mix in a real emergency...

that seems pretty reasonable. Sorry to cause you to write more

 

[chrpai]

Apart from MOD, what else is there to understand

You have to know FO2 because you can know MOD. But, feel free to dive any gas you want. I don't care.