Advanced nitrox

Published by rdevanney on

advanced nitrox

Advanced Nitrox


The next step after completing intro to tech or sidemount is to learn more about dive planning. Being able to follow a dive plan is essential for decompression diving. Advanced nitrox is designed with this in mind. Decompression divers also use higher mixtures of oxygen. Advanced nitrox introduces the equipment and procedures required to do this safely. You will practise setting up and handling a decompression cylinder, and learn a safe and effective gas switching process.


There are numerous options for learning this type of diving in terms of which agency to gain a certification with. I’ll focus on the last two agencies that I was teaching under, TDI’s advanced nitrox, and Raid’s deco 40. With TDI, you won’t be certified to deco dive, but will be allowed to use higher mixtures of oxygen in a decompression cylinder, and dive to 40m (130ft). The point of advanced nitrox is to lay the foundations for the next course; decompression procedures.


With Raid deco 40, you will be certified to dive to 40m (130ft) and undertake no more than 10 minutes of decompression. Deco 40 is a funny one. It’s aimed squarely at recreational divers. Raid believes that many divers are put off by tech, so they created this course to be completed on a single tank with an additional separate cylinder.


It seems more sensible to encourage divers to learn advanced nitrox or deco 40 in equipment that will allow you to progress effectively to the next level. Sidemount is an ideal configuration for recreational divers who don’t like the idea of using a twinset.


One fantastic thing about the Deco 40 course is that you can choose to learn to use trimix, which is a great way to show the benefits of using helium in your gas.


Advanced nitrox/Deco 40 requires 6 dives minimum, and takes 4 days to complete. As with all other of my tech courses, you would do theory, land practise, and open water dives. A pool session is also completed with Raid.


Whilst i’m qualified to teach technical diving with TDI, SSI XR, PADI TecRec, IANTD, and Raid, it really doesn’t matter which course is run. Students learn my way of tech diving at that level. Physiology doesn’t change between agencies, neither does deco theory, or how you handle an out of gas emergency for example.


The differences between equivalent qualifications lies with the limits of the final certification, the rules that the instructor needs to follow during the course, and the specific set of skills that must be practised and performed.


Theory involves more in-depth dive planning, which includes using nitrox mixtures up to 100% O2. Decompression theory and diving physiology is also covered in more detail.


The skills that are practiced include recapping those learned during intro to tech, and additional skills relating to the use of an additional cylinder, including:


  • Gas switching
  • Free flowing deco reg
  • Out of deco gas
  • Staging and retrieving the deco cylinder
  • Towing an diver with an extra cylinder- underwater and on the surface
  • Ascent practice, including gas switching
  • Toxing diver rescue
  • Wing failure
  • LPI failure


Each dive revolves around the student planning a dive using software, and folowing that plan during the dive from start to finish.

Advanced nitrox provides a solid base for the next level of diving- decompression diving.

The minimum prerequisites for starting this course include:

  • 18 years old
  • Advanced OW diver
  • Nitrox diver

The minimum prerequisites for starting this course include:

  • 18 years old with parental consent
  • Advanced OW diver
  • Nitrox diver

Header image photo credit: James Emery Photo

Decompression diving

Training overview