PADI Divemaster Internships: Why dive using enriched air nitrox?

Continuing our series of articles focusing on our PADI Divemaster Internships, this post examines why some divers choose to dive using nitrox?

Browsing the Simple Life dive internships Thailand micro site, you’ll notice that some of our longer gap year internships include PADI Specialty courses, one of which is the PADI enriched air diver specialty. But what is enriched air nitrox, and what advantages does it offer when scuba diving?

The Limitations of Diving with Air

Most of the time when scuba diving, we dive using air. The good thing about air is it’s cheap and readily available – all we need to do is filter the air and run it through a special breathing air compressor and we’re good to use it for scuba diving.

Remember that air is made up largely of two gases – oxygen (about 21%) and nitrogen (about 79%), with a few other insignificant traces.

When we go scuba diving, the regulator system delivers air from the scuba tank at the same pressure as the surrounding water. That means that when we’re scuba diving, we’re absorbing much more oxygen and nitrogen into our body than normal.

Scuba diving within normal recreational depths (i.e. down to 40M), oxygen isn’t an issue as our body metabolizes the O2 which we exhale through the regulator as waste carbon dioxide. But, whilst at depth we’re accumulating nitrogen in our body absorbing more and more nitrogen throughout the dive. At the end of the dive when we make our slow ascent to the surface and the surrounding water pressure reduces, that excess nitrogen must be released. That’s why we always make a slow ascent, giving our circulatory and respiratory system plenty of time to release the excess nitrogen which we exhale through the regulator.

So, it’s nitrogen absorption and elimination which limits our dives, determining how deep we can dive and how long we can stay down for.

On shallow dives (say 0 – 20M), allowable bottom times are very long so scuba diving with air is the ideal choice. But, when we move into the 20-35M range our maximum allowable bottom time becomes significantly shorter. This especially true if making multiple deep dives in one day, or repetitively diving for several days in a row (typical of working as a PADI Divemaster or joining a multi-day scuba diving live-aboard).

So if we want to enjoy a longer bottom time on repetitive, deeper dives we need an alternative. The answer is enriched air (nitrox).

What is Enriched Air / Nitrox?

In enriched air Nitrox we add some extra oxygen to air to enrich the mix. In normal diving, it’s common to use nitrox mixes containing up to 40% oxygen (versus air which contains only 21% O2). By adding more oxygen, we reduce the percentage of inert nitrogen, thus lowering the amount of nitrogen absorbed by our body during a dive.

What means that we’re able to stay deeper for longer. Enjoying long bottom times on Koh Tao’s deeper dive sites gives you a great opportunity to enjoy some of the island’s more spectacular marine life, such as checking out the sharks and barracuda at the Chumphon Pinnacles.

Scuba diving using enriched air does introduce a few complications not encountered when diving with air (such as special equipment and safety). The point of the PADI Nitrox specialty is teaching you how to dive safely using nitrox, following these special procedures and discovering how to plan your bottom times using the mixed gas.

Scuba Diving with Nitrox as a PADI Divemaster

Being certified to dive with nitrox as a PADI Divemaster offers a couple of big advantages. Firstly, for your own enjoyment you’ll be able to extend your bottom times at depth, giving you an even better opportunity to enjoy Koh Tao’s fantastic scuba diving.

Secondly, you’ll be able to guide groups of nitrox certified divers, making you more employable as a PADI Divemaster.

Nitrox diving is also a first step towards the exciting deep sea world of technical diving and is your first taste of deep diving with mixed gases.