http://www.rebreatherworld.com/decom...ng-do-you.html
I was reading the above thread but did not want to hijack it.
Thanks for your replies it seems I still have more to learn :-) its cool being able to ask questions and getting real answers with any of the crap that can come from some other forums unless I ask a realy crap question...
I did sort know about ppo2 at depth but
Dutchy answer was very well put..
David