Nitrox tanks on a shore jetty

Diving with Nitrox vs. Air: Benefits & Drawbacks of Using Enriched Air Nitrox

First off, Nitrox (also known as Enriched Air Nitrox or EANx for short/to sound super scientific), isn’t some fancy energy drink for divers, even though it kinda sounds like it.

It’s simply enriched air — your regular old breathing air with a higher percentage of oxygen blended in, usually around 32% or 36%, compared to the 21% in normal ai​​​​r.

With more oxygen, that means less nitrogen in the air blend — a good thing, you’d think, since a lot of the health issues that arise in scuba diving come from not sufficiently off-gassing nitrogen before surfacing.

OK, so more oxygen and less nitrogen – it’s simple, right? No drawbacks? 

Not exactly — there are some sacrifices you make when diving with Nitrox, and we’ll go into what those are in a bit.

But first, the benefits! 

Benefits of Diving With Nitrox

A combination of regular air tanks and Nitrox tanks with a tropical background of boats and water

The big win here is more bottom time (who’s not down for for longer underwater adventures?!) on deeper dives — up to a limit, of course.

Because there’s less nitrogen in the air blend that you’re breathing, you absorb less of it in your bloodstream, which means you can stay at depth longer compared to diving with regular ai​​​​​r like you would on the surface.

Another benefit of Nitrox diving is that it can shorten your surface intervals – though frankly, I think the rule of thumb of an hour above surface after an hour or so below is one you should stick to…. but it’s not all bubbles, no troubles. 

Drawbacks of Diving with Nitrox

People with nitrox tanks on the great barrier reef in australia

Diving with Nitrox has its cons too, primarily the depth limitations that you have.

Oxygen toxicity becomes a major thing you need to be concerned with, as you can’t exceed the MOD (maximum operating depth) of 1.4 bars of partial oxygen pressure at a maximum.

If you’re not Nitrox certified yet, that’s probably Greek to you. But in practice, here’s what that means: at a 32% blend, your maximum depth is 34 meters (112 feet) and at 36%, that’s 29 meters or 95 feet).

Going beyond that, you increase the chances of oxygen toxicity, which can lead to underwater convulsions — which is just as scary as it sounds, and it’s often a fatal event, because your risk of drowning is very high if that happens to you.

This means that if you’re doing a deep dive to look for mola mola in Bali, and you see one at 40 meters — you can’t go down beyond your air limit on Nitrox or you risk a major catastrophe.

With air, there would still be hazards, like nitrogen narcosis or exceeding NDL and needing to do decompression stops, but the stakes are not quite as high as the risk that oxygen toxicity poses

You absolutely should be diving with a dive computer when you use Nitrox and keeping an eye constantly on your current depth to make sure you don’t accidentally exceed your MOD (your dive computer will beep or buzz a lot as you approach that limit, so don’t worry!).

Other less intense drawbacks include the fact that you need special training, which usually costs about $200-300 USD to learn.

Do You Need Certification to Dive Nitrox?

Nitrox tanks next to regular air tanks with water background

Yes, you need to be certified to dive with Nitrox. 

It’s not rocket science, but it’s essential to learn about gas analysis, oxygen exposure limits, and planning your dives with Nitrox.

Other Factors to Consider When Diving with Nitrox

Nitrox tanks and big blue rope with the sea in beautiful turquoise blue colors behind it

You also need to analyze the air content and verify it before each dive, which is easy enough to do, but it’s one more step that you can’t miss.

You also need to set your dive computer to the correct oxygen percentage for your dive computer to calculate your NDL properly.

Plus, Nitrox is typically more expensive than your standard air fill — very few dive shops will offer Nitrox for no additional charge (but big props to those who do!).

Plus, not every dive shop will even offer Nitrox!

Benefits of Diving with Air

a regular air tank while scuba diving

The benefits? It’s the gold standard.

It’s cheaper, available literally everywhere, and perfectly fine for most recreational dives.

Plus, like I said before, the oxygen toxicity risk is lower.

While technically, you can get oxygen toxicity with regular air, you have to go really deep for that to happen — far beyond your recreational limits.

Since the air we breathe (that then gets bottled for scuba diving) typically contains 21% oxygen, you only would reach a potentially toxic PO2 number around 57 meters or 187 feet down… definitely not your average dive profile.

You’d need to learn technical diving and dive with trimix if you were going to dive that deep!

Drawbacks of Diving with Air

a regular air tank of a diver approaching a shore dive in bonaire in the caribbean

The major issue when it comes to diving with air is the limitations on bottom times.

Primarily, the main issue is just how seriously your bottom time allowance decreases on repetitive dives.

If you do just two dives a day, this typically isn’t a big issue.

But if you’re doing liveaboard diving, where you dive on average 4 times a day, this can definitely start to be noticeable!

Deciding to Dive with Nitrox vs. Air

Scuba divers on the zenobia wreck in cyprus

Essentially, whether you choose Nitrox or air, it really depends on your dive plan, budget, and personal preference.

Sometimes Nitrox really isn’t necessary — if you’re doing a shallow second dive where you’re diving at around 10-15 meters (33-49 feet), you’re rarely going to hit your NDL before you start running low on your air, anyway.

But if you’re doing repetitive dives, diving deeper (but not too deep) and wanting longer bottom times, or want to test the anecdata that Nitrox makes you less tired after diving, Nitrox might be your new dive buddy.

But if you’re cool with standard dive times and looking to save some cash (for that awesome post-dive meal that always hits so much better), then air diving will usually be perfectly suitable.

I’ll be honest: I dive Nitrox whenever I am able to now. 

It offers a little bit more conservativeness on my dive profiles and I want to decrease my risk of a DCI as much as possible.

While on my first and deepest dive, I often approach that pesky NDL, but on subsequent shallower dives, I find I’m staying further away from it, which means that I am doing a more conservative dive profile overall throughout my dives.

Diving to your computer’s limits increases your risk of a DCI no matter what gas mixture you use, but if you dive with Nitrox, you will find it easier to stay within the limits of your computer while still having the dives you want.

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