Pony bottle, 30fc or 40cf?

[NightLife]

I know there is not a huge difference in size, but I don't want to buy something that is bigger then needed. Do you guys/gals that do deco dives use a 30 or 40cf bottle?

[RoadRacer1978]

No experience in the matter, just a lot of research on the matter myself. I am planning on getting a pony as well and have contimplated the same question 30cf or 40cf. I think it would mainly depend on what you are planning do with it. A deco dive, just a redundant air supply. How deep are you going to be planning the dive? How much air do you need to reach the surface, how long is the deco stop and how much gas do you need. What is your SAC so you can properly plan on the amount of gas you need.

With my research I am leaning more towards the 40cf. My plans are for now using it as a redundant air supply and eventually as a deco bottle later on when I move in that direction. To me you can't have too much gas when the difference in size is minimal.

[skdvr]

I just purchased a 40cf and do not do deco but plan on it in the future as well. This is what was recommended to me by a few people on this board. I dove with it for the fist time this weekend and I hardly noticed it was there. It seemed so huge when I pulled it out of the box and thought about it hanging on my d-rings. Really though I hardly noticed it at all. I was even on the bottom most of the time picking up trash and it never really got in my way at all. I know that I will have plenty of redundant air for any dives that I plan in the near future.

If I were you I would just get the 40cf. It can never hurt to have more air than needed.

Phil

[ScaredSilly]

Std is a 40 cuft. But I have both as I can put pure O2 in the 30cuft.

[terrillja]

I have a 30CF, it is the same height as my AL80 minus the boot, so it sits on the boot, and the valves are at the same height. It's nice, since it prevents the 30 from sliding down. I personally use the zeagle pony mount, it is cheap (25) and very secure.

[texdiveguy]

I use a 19cf as a recreational pony bottle, plenty large enough for NDL profiles. My staged deco cylinders range from a 50cf to 80cf and use a steel 72cf for 02 or additional bottom mix as needed.

[fire diver]

Originally Posted by NightLife

I know there is not a huge difference in size, but I don't want to buy something that is bigger then needed. Do you guys/gals that do deco dives use a 30 or 40cf bottle?

What are your plans for this tank? You say "pony" then talk about "deco."

A pony tank is a small, completely seperate tank filled with (typically) air for use in emergency OOA situations. A deco tank is filled with a specific mix for completing deco obligations faster than with backgas alone.

For a pony, an AL19 or 30 is most common. There really IS a size jump from the 30 to the 40. If you plan on using this for a deco tank, then I would suggest a 40.

FD

[NightLife]

Plan on using it as a deco tank. I tried a 30cf and it was nice. Now i'll try a 40. I guess for the little difference in size, a 40 wouldn't hurt. Plus I might be able to use it for 2 dives. On the 30 I used about 1400 PSI in about 16 min at a avg depth of 20 feet.

[texdiveguy]

Originally Posted by NightLife

On the 30 I used about 1400 PSI in about 16 min at a avg depth of 20 feet.

SAC= .54CFM

[paintsnow]

Originally Posted by NightLife

Plan on using it as a deco tank. I tried a 30cf and it was nice. Now i'll try a 40. I guess for the little difference in size, a 40 wouldn't hurt. Plus I might be able to use it for 2 dives. On the 30 I used about 1400 PSI in about 16 min at a avg depth of 20 feet.

wait, are you actually using the bottle as a deco right now? or are you using it to extend your bottom time

as a pony bottle you shouldn't be using it at all unless its an emergency