Yesterday I completed the BSAC Compressor Operator and Nitrox Blender courses.  These were very challenging, not so much in terms of the contents, which are straightforward enough, but the logistics to actually make it happen. It took – literally – months after doing the theory session to organize a date for the practical work, which we agreed three weeks before, then on the day, it turned out that only I could make it! Special thanks to NI CY for going ahead with just me, but as he said, the tanks needed filling either way.

To be a good blender requires a lot of experience with a particular setup, for example on the equipment we used, no-one knows the actual fill rate, the only way to tell is with a stopwatch and an analogue gauge, and we checked temperatures with our hands and the cylinders were either “warm” or “cool’. Getting an accurate blend means just knowing that on compressor W in ambient condition X, over/underfill the O₂ by Y bar, then the air by Z bar, and it’ll all turn out right when the temperature stabilizes. Doing it every day you would quickly develop a feel for it. For now I’ll leave it to the professionals but if at some point I’m diving enough, or in a remote enough location, that getting a J of  O₂ and a small compressor is worthwhile, I’ll have that option.