| Most my diving has been air + O2 deco, the reason for this were a small stage (we have low breating rates so 3 litre is massive along with twin 10's of air) so I can see where you are coming from.
If you have easy access to nitrox (and know your dives in advance) then nitrox + O2 is very compact and a nice compromise
As for what the time and depth is ..... Depends on the planning tools and if you choose to do deep stop etc etc.
I was generally doing 20 mins mandatory stops using a vytec 50% RBGM (pre DS) and 20/85 GF Buelman.
For the 30 to 50m depth ranges it really does not seem to make any difference in total run time if you use 50% or 100% (and I could get 100% more easily than 50 !)
A good rule of thumb is that O2 deco will halve to 6m (and shallow shops) .Using O2 you can do the 5,4,3,2,1 metre stops at 6m with out lenghtening the stops !
This type of deco setup is not very "normal" but works wonderfully for some.
If you are near rebreather friendly dive shops then you can get o2 top offs, which are actually cheaper per dive than 50% fills (as you only pay for what you use)
I think in the BSAC I'm not supposed to be using o2 at 6m, but I did a TDI cert which says its ok !
Tony  |