Have you been diving in a group and one person had a green and yellow band around their tank and you wondered why? This is because that particular diver was using nitrox.
An often misconception among scuba divers is that if you dive with nitrox, you can dive deeper… This is wrong.
Why?
Read on to find out more!
What Is Nitrox?
Nitrox is a mixture of oxygen and nitrogen, also called Enriched Air Nitrox (EANx) because of its increased oxygen percentage.
Whether you are a recreational or technical scuba diver, you can use nitrox when diving, however, there are some slight differences that are worth mentioning.
Yet another misconception is that nitrox contains more nitrogen. If you are a recreational diver and you use nitrox, it will help your body absorb less nitrogen as it contains more oxygen, for example, nitrox mixes usually contain more than the usual 20.9% oxygen, but it should never exceed 40% oxygen.
Technical diving uses two nitrox-based mixes:
Nitrox I: 32% oxygen, 68%, nitrogen (EAN32)
Nitrox II: 36% oxygen, 64% nitrogen (EAN36)
When nitrox is being used it should be clearly marked as seen in the photo below.
The industry standard is to mark the tank with a wrap and a label or tag to identify which nitrox mix is being used. The tank wrap should be 10-13 cm wide and yellow/green in colour.
Does Nitrox Allow You to Dive Deeper?
No, and anyone that tells you nitrox is used for diving deeper is telling you one big fat fib… When we breathe more than 21% oxygen, we are required to stay at a shallower depth. So, if you want to explore greater depths, it is best to stick to regular air.
This misconception comes from the confusion of divers on nitrox being able to have longer bottom times and generally, longer dives.
So, Why Should You Dive With Nitrox?
There are four advantages to scuba diving with nitrox, let’s check them out!
1. Longer Bottom Times
As you will absorb less nitrogen, you can stay underwater for longer and you are less likely to get decompression sickness (DCS) - YAY!
However, this doesn’t mean you should push your limits… When diving with nitrox you should NEVER go over your maximum depth or bottom time. This means checking your pressure gauge (SPG) often and setting your dive computer alarm. Setting an alarm will warn you as soon as you reach your maximum depth.
So, if you are a diver who loves searching for macro or muck diving, then nitrox may be a good option!
2. Feeling Less Fatigued
While there is no scientific research…yet, many scuba divers have reported they feel less fatigue when diving with nitrox.
This is because many divers think that when less nitrogen is consumed diving, fewer micro-bubbles will form in your bloodstream, and therefore less decompression stress which can make you feel tired and drained after diving.
However, as said, we keen divers are waiting for some real evidence to back up our theories!
3. Longer Dive Times
Diving with regular air can be disappointing for many divers. Short repetitive dives often leave many exciting environments unexplored, but by diving with nitrox, you get more repetitive dive times because you absorb less nitrogen on the first dive.
It is estimated that you get 5 more minutes at 20 m than you would diving with air, and while that may not seem that much, if you are a keen diver, you know how precious an extra 5 minutes underwater is!
4. Shorter Surface Intervals
If you plan to do multiple dives, you may consider using nitrox as it gives you shorter surface intervals. You will have less nitrogen to get rid of, making your time at the surface to de-gas fly by.
But, wait, you don’t want to forget about your dive buddy!
If your dive buddy is not diving with nitrox then wait until their surface interval period is over. To do this you should refer to your dive computer and/or dive tables before hitting the water again.
What Are the Disadvantages & Risks of Diving With Nitrox?
Despite all the pros to diving with nitrox, there are also some disadvantages and risks you should know about. Understanding these is critical for both your safety and others.
Two Reasons you may reconsider diving with nitrox, include the following:
Nitrox Is Not Suitable for Deep Diving
Back to the misconception that diving with nitrox allows you to dive deeper. Nitrox is not suitable for deep diving.
Diving at great depths makes nitrox poisonous, therefore, you will need to complete special training before you can dive with nitrox.
Oxygen Toxicity
As previously mentioned, nitrox contains more oxygen than a regular scuba tank, putting you more at risk of oxygen toxicity.
This is why thinking about your oxygen limit before your dive is extremely important. Oxygen limits focus on your lung’s exposure to oxygen and how long you can breathe it underwater.
Acute oxygen toxicity when using nitrox can cause distorted vision and convulsions, and in severe cases, you could drown. This is why I am again repeating that keeping a close eye on your maximum depths and oxygen exposure is essential.
Nitrox Vs Diving With Air
So, what should YOU use when scuba diving? Well, that’s up to you, but I have listed the pros and cons.
But wait, there’s more…
There are two more factors you may want to consider before breaking your nitrox virginity.
The Cost: Nitrox generally costs more than regular air because it takes trained divers and shop workers to produce nitrox gas.
The Availability: Even as nitrox is being more popular, you will rarely see nitrox in most dive shops and diving destinations.
Does Scuba Diving With Nitrox Require Certification?
Absolutely! Diving with nitrox can put you in danger underwater if you do not understand how it works, which is why you must complete special training.
Completing an enriched air nitrox speciality will help you understand how nitrox works, the depth limits, and how you’ll have a safer and more enjoyable dive.
During an Enriched Air Nitrox course, you will learn how to:
Dive with nitrox
Fill a tank with nitrox
Put the right markings on your tank
Use an oxygen air analyser
Set up your dive computer
Use special air tables and gear specifically designed for nitrox diving
So, there you have it, now you should know why scuba divers use nitrox, and more importantly if you are taking the plunge with a yellow/green banded tank on your next dive!
If you have any other questions regarding nitrox, drop me a comment below and I will do my best to answer.
Written by Darby Bonner