Octi vs. Spare Air

[Brian2MN]

Thanks for all the information everyone. I guess I won't be buying one, I'm glad I asked before I bought one. Just in case I gave myself a bad name here, I'm not planning to run out of air or planning to push myself to that point on a regular basis. The only thing that's got me concerned about diving right now though is the idea of running out of air. I like the idea of knowing that I have a backup no matter what. I bought a computer, so I don't antipate running out of air--it's like the warm blanket analogy someone made here.

This brings up another question. I made the mistake of buying a 1st stage, reg, and octi that I later found out would be bad in cold water. I got a mares MR12 Axis and the matching octi. I thought I'd go the cheap route, but later found out this wasn't the best idea. I have since bought the Mares Proton Ice (I know there is some debate about this product too...so please don't lecture me on that) My question is this--I have heard that freezing typically happens in the 1st stage. I have a better 1st stage now, so could I get by with my MR12 Axis octi, or should I really need an upgrade for that too?

I'm going to be diving mainly around here and would like to try ice diving sometime. Can I get by with the octi I have now, or would that be too risky?