The allure of diving deep is one that appeals to many divers and is driven by curiosity and the desire to explore. Having the right kind of diving air mix is critical if you want to go deep.
Even casual recreational divers along a reef wall wonder what’s a little bit deeper. When you can’t see the bottom, when it just turns into a blue haze in the distance far below, you can’t help but wonder what’s down there. In fact only 1% of the deep ocean has been explored. More is known about the surface of the moon than the deepest parts of the ocean. It’s the ultimate frontier.
Divers have developed ways to travel deeper, even though diving deeper takes more technical skills, certifications, and risk. In order to reach the deeps, different air mixes are used. Most divers use regular air to dive, which is 78% nitrogen, 21% oxygen, and 1% other gases. It allows dives to around 40 meters. Mixing air in different percentages changes things.
In recreational diving, divers can be certified to use enriched air, commonly called nitrox. Nitrox decreases the percent of nitrogen and increases the percent of oxygen. Typical mixes are 32 or 36, which specifies the amount of oxygen in the mix. The percent of oxygen also dictates how deep a diver can dive. Nitrox is ideal for divers on a week-long dive trip because it allows for longer dives, reduces risk of decompression sickness, allows fewer and shorter decompression stops, and reduces fatigue. It doesn’t allow you to go as deep as other mixes because oxygen toxicity becomes a problem. It is an ideal air mix for recreational diving and is the certification you need before pursuing other air mixes and technical diving jobs.
Technical diving is where the air mixes really come in. By changing the percentages of gases, you can dive deeper.
These mixes – trimix, heliox, and hydrox – require extra care in the filling procedures, extra air cylinders, advanced knowledge of diving physics and anatomy, travel air, and each tank costs quite a bit more.
Trimix is the most common air mix. It mixes three gases – oxygen, nitrogen, and helium. The percentage of helium decreases the amount of nitrogen and oxygen and allows divers to reach a max of 100 meters. With trimix, extra cylinders and travel gas are required. Travel gas is an extra air cylinder that allows you to travel through the shallow depths safely.
Heliox is the next most common mix. It eliminates nitrogen and only contains helium and oxygen. With heliox you must use travel gas through shallow depths. This mix is most commonly used with commercial divers. Divers can dive as deep as 300 meters with little risk of decompression illness. Unfortunately, the world’s helium reserves are running low and this boosts the costs of using heliox.
The search is on for a new, better air mix. Hydrox may be the answer. It is a mix of hydrogen and oxygen – two cheap, natural gases. While hydrox is still in its experimental stages, it has the potential to be the air mix of the future. It has no side effects, no decompression sickness risks, and is fully breathable at all depths. Unfortunately, hydrogen is highly flammable, which can be a problem.
Air mixes takes a high degree of skill to mix and use. The mixes give divers the ability to reduce risks and increase depths. Overall, the benefits of air mixes outweigh the risks for most divers. It is up to you to become certified in enriched air if you want to explore the ocean’s depths.