What is Nitrox?

If you have recently started scuba diving you have probably heard the word Nitrox, or perhaps seen it being used by other divers on your dive boats. Those yellow and green bands sure are hard to miss! So presumably by now you may have the question, “What is Nitrox?” circling in your mind, and hence you found your way to our blog. While we could get all technical and try to give you a quick lesson on Nitrox, we have decided to break this down into simple terms in a real-world application scenario. We’ll save the technical stuff for the classroom.

Life without Nitrox

I can remember my first dives on the C-53 wreck in Cozumel. This was long ago, prior to my professional career and, more importantly on this dive, before I was nitrox certified. On this dive I remember the underwater visibility was amazing and the shipwreck itself was teeming with vibrant marine life. This was my first wreck dive ever and I was instantly hooked! However, my dives were cut short that day. The Divemaster for that dive had me surface long before I ran out of air. I was confused and disappointed.

Back in those days I was not diving with a computer. Not to date myself, but dive computers were not yet mainstream. So, when my Divemaster signalled for me to surface, I was not really sure what was going on. Once on the boat my Divemaster tried to explain to me something about “no decompression limits” and “not using nitrox” but all I remember was being confused and still focused on my disappoint from missing those precious minutes on that incredible dive.

How Does Nitrox Help?

As you would have learned in your Open Water course, our body absorbs the non-required gas Nitrogen while we are underwater. And thus, the time we can spend enjoying this amazing underwater world is majorly limited by the absorption of Nitrogen by our body. Since its a non-required gas for our body, we can safely absorb only a limited amount of Nitrogen before we must slowly ascend and finish our dives.

However, with Enriched Air Nitrox, because of the increased Oxygen percentage and thereby reduced Nitrogen percentage in our breathing gas mixture, we can significantly change the amount of time we can spend underwater. Less Nitrogen in our cylinders results in less Nitrogen absorbed by our bodies giving us more time underwater! Sounds simple, right?!

Nitrox Test Begins

Now 17 minutes into the dive, we can clearly see, the “No Decompression Limit” (aka NDL) time of 44 minutes in the Nitrox computer is exactly double of the “No Deco” time in the Air computer. Both computers have been into the dive for 17 minutes and both are at 67 feet depth. Okay, so one photo 17 minutes into a dive should immediately create a clear picture for you but let’s not stop yet. We still got dive time remaining!

Nitrox for the Win!

What these next few photos will show you is, if you were continuing your dive with Air, you would have already broken one of the Golden Rules of recreational diving about No Decompression Time Limits – Do Not Exceed your NDL. We can see this on our AIR mode computer. While Martin did ascend slightly to 60 feet at the 44 minute mark, the AIR mode computer is already in Decompression procedures.

However, in direct contrast, the 32% Nitrox computer says you can safely enjoy the underwater world for an additional 24 minutes.

On the Safety Stop

Finally, Martin has ascended to his 3-minute Safety Stop. This photo hammers home the safety aspect of Enriched Air Nitrox. With Nitrox, we are showing 65 minutes of bottom time remaining. In stark contrast, we have 4 minutes of Decompression time, 3 minutes of Safety Stop time, and an end-of-day diving situation with Air.