Nitrox 28 in one tank and smooth classic air in the other

[divealaska]

I hope I didn't sound too harsh. Just want you to be safe

 

[eelnoraa]

I am also with divealaska. Why make you life more difficult then it needs to be?

But if you insist on pony, why not just fill it with EAN28 like your back gas? cost you less than $10. And I don't suppose you need to go to your pony often, so one fill should last your quite a while

 

[Searcaigh]

The difference between using air or EAN28 is not significant in making an ascent from say 30M to surface including a 3 min safety stop. I have not done the calculations (I am sure somebody will though), but I doubt it is going to push you into a situation where you can't dive after an hour surface interval.

Suunto Vytec has the capability of using three different gas mixes, which you can switch to under water if set up correctly.

 

[RTee]

I assume you have EAN 28 as back gas because you are looking to dive down to the limit of rec diving which is 130 ft. If you normally use EAN 28 as backgas, then have your pony filled with EAN 28 as well and there will be no need for gas switching on your computer. If you normally use air, then EAN 28 will keep you the the plus side if you ever have to switch to your pony. If you normally use EAn 32, the difference will be minimal. BTW, what backgas do you normally use???

In my book, there is a difference between equipment malfunction and emergency and both could force you to switch to your pony. In some situation, handling badly a simple malfunction could result in the end state of a dive emergency.

 

[Dub5ire]

a pony is a redundant air supply, why would u leave it home?

 

[Wetsuit 4 life]

A pony can be used as a redundant air supply or used as just extra gas source that is included in the total planed gas volume, in this case the extra gas source had a different mix then my other gas source so it was left at home. And good thing too the sites entrance conditions would not have made moving an al80 pony very difficult

Cheers