TDI Advanced Trimix Diver       This five days course provides the training required to competently and safely utilize breathing gases containing helium for dives that require staged decompression, utilizing Nitrox and / or oxygen mixtures during decompression to a maximum depth of one hundred (100) metres. The objective of this course is to train divers in the benefits, hazards and proper procedures of utilizing custom oxygen / helium / nitrogen mixtures as breathing gases. Pre-requisites: Extended Range Diver or equivalent, 100 logged dives, of which 25 must be deeper than 30 msw. Minimum 18 years of age.