Nitrox — often called enriched air Nitrox or EANx — is a breathing gas containing a higher percentage of oxygen and a lower percentage of nitrogen than ordinary air. Recreational divers commonly use it to manage nitrogen exposure on suitable dive profiles. The important point is that Nitrox is not “better air” for every dive. It has advantages, but it also introduces oxygen-exposure limits that must be understood and respected. Why reduce the nitrogen fraction? When you breathe compressed gas underwater, nitrogen is absorbed into body tissues. Using a mix with less nitrogen can extend the no-decompression limit for certain depths compared with using air, depending on the mix and the dive computer settings. Does Nitrox let you dive deeper? No. In fact, oxygen exposure creates a maximum operating depth for a given Nitrox mix. A diver must know the oxygen percentage, calculate or confirm the maximum operating depth and set the dive computer correctly before the dive. Going beyond the planned oxygen-exposure limit can be dangerous. This is why formal training and gas analysis matter. When can Nitrox be useful? Repetitive recreational dives over several days Profiles where no-decompression time would otherwise be a limiting factor Liveaboard or holiday diving with multiple dives per day Certain shallower or moderate-depth profiles where an appropriate mix provides a useful margin Nitrox does not remove decompression risk Using enriched air does not make a diver immune to decompression illness. Depth, time, ascent rate, hydration, workload, individual susceptibility and other factors still matter. Divers must follow appropriate training and their computer rather than treating Nitrox as a safety guarantee. You need to analyse the cylinder A Nitrox diver should know the actual oxygen percentage in the cylinder being used. Training covers how to analyse a cylinder, confirm labelling and ensure the computer is configured for the correct mix. Never assume the contents simply because someone says the tank is Nitrox. Why computer settings matter If your computer is set for air while you are using Nitrox, you may not be using the intended advantages of the mix. If it is set for a richer oxygen mix than the cylinder actually contains, the displayed no-decompression information may be inappropriate. Accurate settings are part of the pre-dive routine. Is Nitrox suitable for beginners? Divers typically add enriched-air training after or alongside entry-level certification when appropriate. The useful question is not whether Nitrox sounds advanced, but whether you understand the procedures required to use it correctly. Phoenix Divers’ advanced diving courses in Koh Tao provide progression options for certified divers. The Advanced Diving Course also introduces a broader range of diving experiences and theory. Use the right gas for the right dive Nitrox is a useful tool, not a shortcut. With correct training it can be an excellent option for repetitive recreational diving, but every cylinder, depth and computer setting still needs to match the plan.