Recreational triox utilizes 30/30 (a helium-based gas) to reduce narcosis and increase the efficiency with which breathing gas travels through the airways. Depth is limited to 120 fsw and bottom times are kept within no-decompression limits. Perhaps more important, this is where the diver begins to experience simulated failures and team resolution of these failures. Recreational triox introduces concepts which are further developed in the Tech I course.
