SDI Computer Nitrox Course

Standard scuba air is roughly 21 percent oxygen and 79 percent nitrogen. Nitrox, also called enriched air, shifts that ratio: more oxygen, less nitrogen. Less nitrogen in the mix means your body absorbs less of it during a dive, which gives you more time at depth before hitting your no-decompression limit, less fatigue after a day of multiple dives, and a wider safety margin on every dive you take.

The SDI Computer Nitrox course is how you get certified to use it. It covers the physiology, the equipment considerations, how to analyze a nitrox cylinder before diving it, and how to program your computer for a nitrox mix between 22 and 40 percent oxygen. The entire course is classroom-based. No dives required.

What the Course Covers

The Physiology of Nitrox

Nitrogen is the component of breathing gas that creates decompression obligation. Because nitrox contains less of it than standard air, you build up that obligation more slowly at any given depth. The course covers how the body processes different gas mixtures, what increased oxygen percentage means for your physiology, the concept of oxygen toxicity and the limits that keep nitrox diving safe, and why mixtures above 40 percent oxygen require a different level of training entirely.

Equipment Considerations

Nitrox requires oxygen-compatible equipment for anything above a standard air mix. The course covers which components of your dive gear need to be oxygen-clean and what that means in practical terms when you rent or own equipment. You will also learn how to read a nitrox fill label and what information it must contain before you dive any cylinder.

Cylinder Analysis

Before diving a nitrox cylinder, you verify the actual oxygen content yourself. The course covers how to use a nitrox analyzer, what a correct and incorrect reading looks like, and how to confirm a fill matches what the label says. You will analyze at least two nitrox cylinders as part of the course requirements.

Programming Your Dive Computer

Standard dive computers default to an air mix of 21 percent oxygen. When you dive nitrox, you need to program the actual oxygen percentage so the computer calculates your no-decompression limits correctly for that mix. The course walks through how to set a nitrox mix on a dive computer and why using the wrong setting with nitrox gives you inaccurate and potentially dangerous information.

What the Certification Gives You

With your SDI Computer Nitrox certification, you can fill and dive nitrox cylinders up to 40 percent oxygen at any facility that offers enriched air. The practical results on actual dives are straightforward.

• Extended no-decompression limits at depth compared to standard air
• Less nitrogen loading means reduced post-dive fatigue, which matters most on multi-dive days and liveaboards
• Increased safety margins on any dive within recreational limits

Many liveaboard operators and dive destinations in Mexico, the Caribbean, and the Pacific offer nitrox as a standard fill option. Some prefer or even require nitrox-certifications. Having the cert opens those options up.

A Note on the SDI Advanced Diver Program

If you are working toward the SDI Advanced Diver rating, the Computer Nitrox certification has a specific rule worth knowing. Because it is a knowledge-only course with no in-water dives, it falls under a special exception in the SDI Advanced Diver requirements: only one knowledge-only specialty can count toward the four required certifications, and Computer Nitrox is specifically is that exception. It does count toward your four Advanced Diver specialties.

Who Can Enroll

The SDI Computer Nitrox course is open to certified SDI Open Water Scuba Divers or equivalent, as well as divers currently enrolled in an Open Water course. Minimum age is 10 with parental consent, 18 without.

What to Bring

This is a classroom course with no in-water component, so there is no gear to bring and no rental equipment involved. Bring your certification card or enrollment documentation and a way to take notes. If you own a dive computer, bring it along, programming your own computer for a nitrox mix during the session is a useful hands-on step.

Frequently Asked Questions

What is nitrox diving?

Nitrox, also called enriched air, is a breathing gas mixture that contains a higher percentage of oxygen than standard air. Standard air is approximately 21 percent oxygen and 79 percent nitrogen. Nitrox mixes used in recreational diving typically range from 22 to 40 percent oxygen. The higher oxygen content means less nitrogen, which reduces nitrogen absorption during a dive and extends your no-decompression limits.

What are the benefits of nitrox for scuba diving?

The three main benefits are extended no-decompression limits at depth, reduced post-dive fatigue on multi-dive days, and increased safety margins compared to diving the same profile on standard air. The fatigue reduction is especially noticeable on liveaboards and any day with three or more dives.

Is nitrox worth getting certified for?

For most active divers, yes. The course is two hours, classroom-only, and the certification opens up nitrox fills at any shop or resort that offers enriched air. If you dive multiple times a day or plan any liveaboard trips, the extended bottom time and reduced fatigue are immediately practical.

How long is the SDI Computer Nitrox course?

The session runs approximately a few hours and is held in the classroom. There are no pool or open water dives required for this certification.

Does the SDI Computer Nitrox certification count toward the SDI Advanced Diver rating?

Yes. Computer Nitrox is a knowledge-only specialty however it is an exception and the SDI Advanced Diver program allows it to count as one of the four required specialties. You still need three other specialty certifications that include in-water dives to qualify for the Advanced Diver rating. 

Can I use any dive computer with nitrox?

Most modern recreational dive computers support nitrox programming, but you need to check your specific model. You must program the actual oxygen percentage of your nitrox fill into your computer before diving so it calculates your no-decompression limits correctly for that mix. The course covers how to do this and what happens if you dive nitrox without updating your computer settings.

Ready to Add Nitrox to Your Dives?

Register for the SDI Computer Nitrox course at divearizona.com or call us at (480) 881-4013. We are open Monday through Saturday 11am to 6pm and Sunday 11am to 5pm, at 18618 S 186th Way, Queen Creek, inside The Shooting Range.

For more information and to see course standards, click here!