CCR Air Diluent and Air Deco Training

[DiveLikeAMuppet]

TDI has three outcomes at mod1, your instructor can certify you based on the progress of the course.

• Air dil no deco, 30 m.
• Air dil deco, 40 m (you need ANDP or similar as a prerequisite).
• Helitrox, 45 m (OC ANDP-helitrox or OC normoxic trimix as a prerequisite, I think theoretically you could do some trimix theory in the course?, and an extra dive), you could also do it as an upgrade.

I personally think that mod1 is just a stepping stone and a bit weird. I did a dodgy mod1 helitrox and already had OC trimix, so obviously I started to dive trimix dil. When your loop has helium, you need trimix bailout. Trimix bailout is not great for deco, so you start to carry a second stage as deco gas… which enables dives that are probably a bit on the edge at mod1 level. So I can imagine that some instructors treat helitrox a bit like mod1.5 and want to have some in water time before getting there.