Nitrox - Trimix

[matt t.]

Last year I took the adv nitrox/deco class, and this spring went on to the tri-mix classes. I never really noticed any impairment during deeper dives (100-160 ft), at least not the pounding, tunnel vision type narcosis you hear about (though I did always feel relaxed, and like things were flowing along pretty smoothly. Slight buzz?) . However I DID notice how clear I was on the deep dives (120-200ft, END of about 65 ft.) during the tri-mix classes. My primary light went out at about 180 as we were descending through a black layer, and it was no big deal to shut it down, clip it off, and go to my back up light. I'm waiting to do some of the same dives on helium that I did last year on air, to see what I may have missed. No doubt about it, the helium does work. The biggest down side I see is the costs associated with nitrox and helium. Doing some of the deeper dives it can cost almost as much for fills as the charter costs. Is it safer? Undoubtedly. Only the individual diver can decide where their depth/narcosis comfort level is, and then determine if the fill costs are worth it to them.