AL30 or AL40 for stage tank

[Scubatooth]

Im looking for a opinon from the board on these two tanks to be used as stages, and im wondering which one would be best for me for right now(based on my diving and build).

mainly for right now it would used as redunency for working with classes for a student to use in the event that something where to happen( so that there not on my gas supply and in my face) but will be converted into a stage once i begin that training(read below).

Im around 5'10" im currently a rec diver but in the near future will be moving up to technical diving (adv nitrox and Deco) in about a year .


just looking for some opinons

thanks in advance

Tooth

 

[Rick Murchison]

I use 80's for stages; I use ponys (30 or 40) for deco gas when they will meet double the planned requirement - otherwise use an 80 for that too. Either a 30 or 40 is fine for a bailout bottle for students.

 

[LUBOLD8431]

Well, there is a difference between a stage bottle, and a deco bottle. It sounds like you are just talking about a safety bottle, which could then be used as a deco bottle. If my assumption is correct, then I would suggest a 40.

 

[miglanc]

I think it depends how many gases you need to make good deco. This could be bad idea to take smaller tank when you need lots of gas. But on the other hand why taking big tank for short decopmression?

 

[SDAnderson]

If you're heading towards technical diving, you might want to settle now on standard bottle sizes. I've seldom seen anything other than an 80 used for a stage bottle. They're also the standard for deco bottles, although 40's are common, too. There's no reason a 30 wouldn't work (assuming that's enough gas) for either but it's not the norm. If I was buying, I'd get the 40. I wouldn't replace a 30, however.

 

[DA Aquamaster]

I have a pair of 30's and wish I had went with a pair of 40's. The 40 is only 4-5 inches longer than the 30, shares the same diameter and is more suitable (and more standard) for use as a deco bottle.

That said though my average deco dive tends to be fairly mild with something like 140' for 20 minutes with another 20 minutes for ascent and 12-15 cu ft of 50% planned for deco (but usually less than 10 cu ft actually used.)

So a 30 is more than enough and getting two dives out of one is normally possible. So in short I won't be buying any more 30's but I also won't be selling mine anytime soon.

Unless I am going a whole lot deeper or longer than I currently do, I cannot see any reason to lug along an 80 when a 30 or 40 is so much nicer to carry.

 

[strider]

I agree with everyone. I have a couple 30s that are fine and all, but a 40 is just a few inches longer and I would beable to get a couple dives with a 40 for my deco gas.
One other thing though, I hate my 30s as pony bottles. They are constantly pulling me and it gets very frustrating. I have tried adjusting weights, but it always twists me a little, even when I sling the 30 as a pony, it's better slung, but still pulls annoyingly. I switched to twins and now if I need a pony I'll just use twins.
My advice for the pony would be to find a good deal on one thats around 19cf or even a little smaller, if that will meet your needs. If its just for Open water students it should be more than adequate and not get in the way too badly. 13cf might be large enough and then you have an argon bottle for your drysuit later.