This May, Aliwal Shoal Scuba is offering its customers the opportunity to become Nitrox certified at the discounted price of R399. This offer is available to all those booking another course through the dive centre, and perfectly complements every level of certification, from Open Water all the way up to Divemaster. Nitrox, or more accurately, enriched air nitrox, has been used in the recreational diving industry for almost twenty-five years, and refers to any blend of nitrogen and oxygen in which the oxygen percentage is higher than that of normal air. Therefore, nitrox can refer to any air mix that contains 22% of oxygen or higher; in diving, the most common percentage is 32%, whilst the recreational limit is 40%. The PADI Enriched Air Diver course teaches divers the benefits and potential risks of nitrox, as well as how to use it safely.

There are a lot of misconceptions when it comes to nitrox, most of them associated with why we use it in the first place. To understand the purpose of nitrox, it is important to understand that when we breathe air at depth, the increased surrounding pressure causes the nitrogen in that air to dissolve into our bloodstream. The time that we can spend underwater is limited by this nitrogen absorption- as we dive deeper and for longer, more nitrogen is absorbed at a greater rate. Our no decompression limit correlates to the amount of nitrogen our bodies can absorb before we must perform compulsory decompression stops or suffer the consequences of decompression sickness. By replacing some of the nitrogen in the air that we breathe with extra oxygen, nitrox reduces the rate at which nitrogen dissolves into the bloodstream.

There are several benefits to reducing the rate of nitrogen absorption. Perhaps the most obvious advantage is increased no-decompression limits, meaning that you can spend longer underwater than you would have done were you diving using normal air. For example, a diver using normal air has a no-decompression limit of 50 minutes at 18 metres; but with a 36% enriched air mix, that limit would be increased to 130 minutes at the same depth. Another important effect of using nitrox is that surface intervals are shorter, as a diver has less nitrogen to off-gas before it is safe to get back in the water. A nitrox diver that followed the same profile as a diver using normal air for their first dive would typically be able to start their next dive quicker, and enjoy a longer maximum bottom time the second time around.

Additionally, as less nitrogen is absorbed into the bloodstream when using nitrox, those divers using enriched air often feel less fatigued at the end of a long day’s diving than they would have done had they been using normal air. Enriched air can also be useful as a safety net for divers that choose to use it while following normal air tables, computers, profiles and procedures. Doing so creates a considerable conservative margin that further reduces the risk of decompression sickness and is sometimes advisable for anyone that may be susceptible to it, i.e those who are tired, overweight, older, have suffered previously from decompression sickness or are diving with injuries.

With that being said, there are some instances in which using nitrox can be dangerous, which is why it is so important to receive proper training before attempting to dive on enriched air. For example, many divers believe that nitrox allows the user to dive deeper than they would otherwise be able to on normal air. In reality, all nitrox mixes have a maximum operating depth at which the oxygen in the air mix becomes toxic- and because all nitrox mixes carry a higher percentage of oxygen than normal air, they become toxic at a shallower depth. Nitrox does not enable a diver to dive deeper- it enables them to dive at the same depth for longer. PADI’s Enriched Air Diver course also teaches divers about equipment considerations that relate to using nitrox; and how to check the percentage and maximum operating depths of your mix before every dive.

The purpose of this course is to teach divers how to use nitrox safely so that they can use it to get the most out of their experiences underwater. At Aliwal Shoal Scuba, we’re all about making sure that our customers have as much fun as possible- which is why we decided to offer a special on Nitrox courses as part of our thirtieth anniversary celebrations. To find out more about the special, or about Nitrox in general, please get in contact via Facebook or send an email to

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