The Scuba Gear Lab

What Is Nitrox Mode on Dive Computers? EAN Settings Explained

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Forgetting to flip a single switch on your dive computer could land you in a recompression chamber—and it happens more often than you'd think. In this episode, veteran diver Ray Hollister breaks down exactly what nitrox mode does, how it recalculates your no-decompression limits, and why getting the setting wrong puts your nervous system at risk. Whether you're newly certified for enriched air or you've been diving EAN for years, this is essential knowledge for anyone breathing anything other than standard air underwater.

  • Your dive computer's nitrox mode adjusts decompression calculations based on reduced nitrogen content in enriched air—feeding it the wrong gas mixture means dangerously inaccurate tissue loading math.
    • Leaving your computer set to a nitrox mixture when breathing regular air is just as problematic as the reverse, giving you less no-deco time than you actually have and building sloppy habits around life-support equipment.
      • The algorithm tracks nitrogen absorption across multiple tissue compartments simultaneously, and switching from air to EAN32 at 60 feet drops your nitrogen partial pressure from roughly 2.3 bar to about 1.97 bar—a difference that compounds significantly over a dive.
        • On multi-dive days, EAN32 can extend your no-decompression time from around 40 minutes to nearly an hour on the first dive, with even bigger advantages by your third tank.
          • Nitrox mode also enforces maximum operating depth limits based on oxygen toxicity—EAN32 caps you at approximately 111 feet, while EAN36 drops that to around 95 feet, and your computer will alarm loudly if you exceed these thresholds.
            • Most recreational computers use Bühlmann ZHL-16C or RGBM algorithms that accept user-defined oxygen fractions, automatically recalculating every tissue compartment when you input your specific EAN percentage.

              • Read the full article: https://thescubagearlab.com/what-is-nitrox-mode-on-dive-computers-ean-settings-explained

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              The Scuba Gear LabBy The Scuba Gear Lab