Nitrox or air? This is a frequent question when it comes to reaching the chosen dive destination. While in our opinion the answer would be “Nitrox forever” may not always be the best option, especially for those divers who like to go up to the sea bottom … even if it is more than 40 meters! In this post we do not want to do a master class on Nitrox, we consider that it is not up to us to make these comments. Here we will see a bit of how the air we load in the bottle on diving trips works and how and when it is better to use one or the other … or even both.

To begin with, for those who have doubts about what Nitrox is, we will say that it is simply an air for diving that carries more oxygen than the pressure air that is usually loaded in the diving bottles. While you are reading this post, you are breathing air (in this case uncompressed), which is approximately 21% Oxygen. The rest, approximately 79% is Nitrogen. A diving bottle loaded with Nitrox (also called EANX by the acronym in English or Enriched Air) contains a higher percentage of Oxygen. Although this percentage can vary from 28% to a maximum of 40%, in diving destinations, the “standard” percentage that you will find is 12L bottles loaded at 32%.

Nitrox has become the gas of choice among most of the traveling divers and the reasons are important. Let’s see them.


Nitrox tank

Among the many advantages that offers diving with this mixture, for us who travel and do a lot of successive dives and then we have to catch a return flight, the Nitrox gives us a margin of safety superior to compressed air, since it allows us  stay longer in the sea bottom without you entering in “deco” (for example at 21m with air you have a limit of no decompression of 40 minutes, with Nitrox 32% you increase your limit of no decompression to 60 minutes). Another advantage is less surface interval between dives and, also a shorter desaturation time that allows us, more time in the sea bottom in successive dives and more security when catching a return flight.

Can I dive deeper with Nitrox?

No. This is a common mistake. Oxygen poisoning can have serious consequences. Unlike the poisoning by Nitrogen, the famous narcosis or drunkenness of the depths, which “warns” with visible effects for you and the rest of divers, if you exceed deep diving with Nitrox you can suffer a sudden syncope that can take you to death. So, the most important thing is not to go beyond the depth limit that your computer marks for the mix you are carrying. Up to that limit you will always be diving more safely with Nitrox than with air.

That’s cool, right? , well these are some of the reasons why we say “Nitrox forever” but in certain diving trips it may not always be the best option.

In destinations where you usually dive deep in search of “big bug” such as Maldives or some areas of Red, etc., the first dive (which should be the deepest) is recommended to do it with air in order to start using Nitrox in the next. You also have the option to do the first one with Nitrox 28%. But attention, now I am going to tell you what happens in a diving boat with Nitrox.

We have reached the dive boat, say for example one in the Red Sea, we look for a sit on the diving platform. Next we leave our diving equipment in the boxes enabled for this purpose and hang the jacket in the bottle as a message ” This is my site. ” Although all of us, who have done the Nitrox course know that the bottles with this mixture are clearly identified with their green stickers, all very nice, sometimes the reality on board is quite another. The first thing they will ask us, is if we are going to dive with Nitrox. If so, they will give us a card with a rope, stopper with rope or any other identification system to place it in the bottle, so the person in charge of the air bottles will know what mixture we want. This is because in a dive boat the bottles do not move from place but they are loaded with hookahs. That means that often (if not always) they load on the same bottle without emptying first, so try to leave the first dive with as little air as possible. Also, if you can open taps without making too much noise (without you being seen because they will close it) while you are changing so that all possible air comes out. It goes without saying, that you analyze your bottle well because it is very possible that in the first dive with Nitrox after one with air you won’t be carrying 32% but less.

The boats usually carry a single analyzer for all divers, so if there is a lot of divers with Nitrox, you have to be patient until you can get hold of the analyzer. Once checked the air, immediately put your dive computer abreast of the mixture you are carrying. This may seems obvious but  is very important to do it instantly, because at that moment everyone walks around putting their diving suits or looking for the analyzer and talking and you can easily get distracted chatting with your dive “buddy” and leave the computer with air … I speak from my own experience.

The analyzers on board (better said, the analyzer) usually it is used a lot during the trip, so always look that it is well calibrated and always, I repeat always be you who do the analysis of the bottle. I saw in the Red Sea a guide that put his finger on the output of the analyzer to increase the percentage of Nitrox …

After leaving the water you will have to write down diving data in the immersion sheet and sign. As you can see, it does not have much complication, but you must be careful.

In many dive boats (and diving centers) Nitrox 32% for 12L bottles is usually free. If you want Nitrox 32% in the bottle of 15L, they usually charge a supplement, the same as if you want Nitrox 36%. Although in many cases the maximum is limited to 32%. In my opinion, for deep dives at the first time in the morning the ideal is to “bribe” the bottle loader to load it with Nitrox 28% this way, you will be able to go down to enough depth and dive safer.

Do I need a special equipment to dive with Nitrox?

Most of the diving equipment is compatible with an Oxygen content of up to 40% and as we have said, on a diving trip it is normal to dive with a mix of 32% so your team is perfectly prepared for this type of diving. diving.

And that is all for now friends. Enjoy!