Hello,

The RB80 was designed to use DIR standard mixes and nothing more. If you are using these mixes then you know the MOD for each mix. The RB80 is more of a gas extender than a rebreather, so using something other than the standard DIR gas set could be very dangerous.

A typical profile would be to have your bottom gas in your mounted tanks (18/45 up to 190').

You would be on OC to deeper than 20', then youo would begin to breath your loop until it was time to deco.

during deco you plug in your deco gas (standard mixes) at the apropriate depths.

I'm not an RB80 instructor, so the best advise here would be to talk to one
directly. If your using a clone you may be out of luck, if it is an RB80 I know an instructor who MIGHT help. ( big might ) Training is everything to these guys, and if your not properly trained getting help could be next to impossible.