How to Set a Dive Computer for Nitrox
Nitrox is a scuba-diving gas mixture that has different percentages of oxygen and nitrogen than regular air. Air typically contains 79 percent nitrogen and 21 percent oxygen. Nitrox for scuba diving is any gas blend that contains more than 21 percent oxygen. The most common of these blends are EAN32 and EAN36 (Enriched Air Nitrox 32 percent oxygen or 36 percent oxygen.) Using a dive computer to manage diving on Nitrox is a safe and easy alternative to using traditional EAN dive tables.
Instructions
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1
Hold the oxygen analyzer up to the valve on the nitrox tank and open the valve very slightly so that a small flow of gas is escaping the tank. Ensure that the stream of gas from the tank is pointing directly into the input of the oxygen analyzer.
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2
Wait for the numbers on the oxygen analyzer to stabilize. Read the number (the percentage of oxygen in the mixture) and write it on the tank for reference. This is the FO2 or fraction of oxygen in the mixture.
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3
Turn on the dive computer and scroll through the menu to find the FO2 or %O2 option. This option varies based upon the computer being used.
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4
Scroll up or down to set the FO2 to match the FO2 written on the tank (from Step 2.)
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5
Scroll the menu to the PO2 option and set it to 1.4 (conservative safe level) or 1.6 (maximum recommended safe PO2 level.)
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6
Accept all settings to lock them into the computer for the upcoming dive.
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Tips & Warnings
Steps 2 through 6: Oxygen analyzers and computers vary from brand to brand and model to model within brands. Always consult your instruction manual to determine the exact sequence for setting FO2 and PO2.
Step 4: For extra safety, round any percentages in FO2 up to the next whole number. Some computers' calculations already add 1 percent to the number entered, so check your instruction manual for confirmation.
Diving is an inherently dangerous sport. This article is intended only for trained and properly certified divers. Do not dive without proper training.
