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Voodoo Gas, Blend it Baby!

Voodoo Gas, Nitrox, or to give it the correct name, Enriched Air Nitrox (EANx) is still a mystery to some people. Why use it, why pay for the course to learn how to use it, and what are the benefits? I found out the answers to these questions many years ago when I did my PADI EANx Course. Back then it wasn’t that common, hence the nickname ‘Voodoo Gas’.

Nitrox Tank

For the uninitiated, EANx is used by divers in order to have longer dives at certain depths due to the fact that the percentage of oxygen is increased. This means that the percentage of Nitrogen is decreased, nitrogen being the limiting factor in depths and times of dives. Normal air is 21% oxygen and 79% nitrogen, whereas the two most common blends of EANx are 32% or 36% oxygen leaving only 68% and 64% nitrogen respectively.

One of my biggest questions, however, remained unanswered – ‘How do we get Nitrox into our tanks?’ – I had a rough idea but it wasn’t until I recently undertook my PADI TecRec Gas Blending Course that this was fully answered!

For the first time in a while the instructor became the student as I was handed my Gas Blending Manual and told to complete Knowledge Reviews 1,2 and 3….now don’t get me wrong but I am used to being the person asking students to give up their evenings to study, now I am being asked! Oh well, for the greater good…

The next morning I met up with Wilco, who was to be my instructor for the next couple of days, and we walked through the reviews, adding ‘meat to the bones’ where we needed so I had a full understanding of how EANx is blended and the possible hazards of the differing procedures and how we avoid them.

Next it was onto the practical side of things and actually learning to fill a cylinder with nitrox rather than normal air. Knees knocking, I followed Wilco to the compressor room and started to learn all about all the workings of the complressor and how to blend different mixtures of gases correctly – but only after a stark warning from Wilco – ‘When filling nitrox, please don’t blow up the compressor room!’ – now I am not usually a nervous individual but that got the sweat trickling down my neck, or was that the 38 degree heat?

Gary Blending Nitrox

So we worked step by step through everything from attaching the tanks to the filling whips (the hoses used to put the Nitrox into the cylinder), to startup steps for the compressor, to how we add the oxygen to the normal air to achieve the desired percentage blend and finally to the full shutdown upon the fill of all the cylinders needed.

Ten cylinders later I felt comfortable in blending Nitrox, as long as I followed Wilco’s expertly written step-by-step guide! I went on to complete the rest of the Knowledge Reviews and take the final exam…scored an 88%…not too shabby!

I have been regularly blending and filling our Nitrox cylinders since my course and am getting more comfortable each and every time. I may even be able to ditch the step-by-step guide sometime soon!

For anyone who hasn’t got their PADI Nitrox Certification yet I highly advise doing it, maybe in conjunction with your PADI Advanced Open Water Course and that way, you too can experience ‘Voodoo Gas’ on your next dives!

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