Nitrox...not a very hard course once you master a couple of principles and formulas. My instructor was a relatively young but very keen individual. We went through the do's and don't of nitrox diving, the formulas to accurately find the Equivalent Air Depth based on actual depth and mix, figure out best mix for planned depth, etc and we also used EAN 32, EAN 36 and air tables (for non standard EAN mix) as well as computer for planning dives. as part of Plan the dive and dive the plan, we also covered limiting factors for specific dives such as gaz carried (based on SAC and planned depth), max and contingency depth for mix being used, O2 toxicity, etc. In fact, a year later, I went through the TDI manual of Advanced Nitrox (I am planning to take next spring the Advanced Nitrox/deco proc combination course) and realized I was pretty well familiar with most of the content.
Nitrox vs Air...interesting debate. I just returned from Cozumel where I had a free Nitrox upgrade due to the fact I was qualified and so did my girlfriend. That was a no brainer for us especially when we could have dove as much as 4 times a day (max we did was 3).
Around here, my LDS does not charge a premium for Nitrox fill. With my girlfriend, my son and myself all EAN qualified, I will normally carry EAN 32 in my set of doubles (O clean) and all single tanks (not O clean) and then adapt accordingly as to the dives I am planning, the locations and the type of fills available.
