From the first time you try scuba diving you realise that moving underwater is not as easy as you thought. All the new equipment, the heavy tank and unfamiliar fins at the beginning feel a bit uncomfortable. Even swimming in a straight direction is not so straightforward, and then you also have to take care of the depth you’re standing and it all becomes at least… overcoming. This is normal; you’re in a new environment, with new equipment and you have to take care of a lot of details. This is something every beginner in diving experiences and even for the more experienced ones, sometime, showing a good buoyancy control does not come entirely natural. Let’s see together what you can do to master this very important aspect of scuba diving and how to turn into an easier and full-of-fun experience. Equipment that fits Make it easier for yourself, use good equipment that fits well. If you BCD is too big it will make the tank roll form one side to the other, causing you to roll with it. The tank is the heaviest part of your gear and if it is not properly fixed it will drive you crazy…

Has it ever happen to you to be diving an amazing spot and right at the peak when the manta was passing by or when the sharks started to get closer the dive master had to close the dive because someone in your group was low on air? And, maybe, that someone was you? We thought it was useful to write this guide because we believe that there is not enough information about air consumption and breathing techniques in the standards of scuba courses and we wanted to create a comprehensive guide to help people to consume less air thus enjoying more their dives. From the first few dives you realise how important is to consume little air but how can you control that? What makes you use a lot of air? Let’s first analyse what influences the quantity of air the we use. Body structure Of course one of the first things that you have to take into consideration when analysing your air consumption is your body. A 12 year old girl will use much less air than a 35 year old rugby player; does this make sense? The girl’s lungs are way smaller, needing less air to be filled up…

All modern SCUBA tanks use one of two kinds of valves: DIN or INT (“yoke”) valves. Regulator first stages have corresponding connections, and one won’t fit on the other regulators and adapters. What is an INT / yoke valve? INT is an abbreviation; it stands for ‘International’ and it’s by far the most common type of valve you’ll see in recreational diving (outside Europe). You can easily identify a yoke valve by the o-ring seal on the front of the valve and dimpled guide for the yoke on the back. The regulator is screwed, yoke-style, onto the valve where air pressure (and a properly-greased o-ring) maintain a tight seal. What is a DIN valve / adaptor? DIN is an acronym – Deutsche Industrie Norm. Unlike yoke valves, DINs have a threaded opening where a regulator screws into the valve, and no o-ring (it’s found on the first stage in DIN systems). DIN valves are rated for higher pressure than yokes, making them indispensable for technical/deep diving. Almost all tank manufacturers offer both tank valve systems, and DIN/INT adaptors for your regulator are readily available – it’s easy to switch between the two while travelling.

The simple answer: “about an hour”. But it’s more complex than that: how much air a diver consumes obviously depends on their level of physical exertion. But how long a scuba tank lasts also directly depends on the depth at which it’s used. There are varying sizes of cylinder, of course, and the size you choose will affect how much air it can contain and how long the tank will last at a given depth, but the most common you’ll encounter are standard 12L, 200-bar scuba tanks. The deeper you dive, the denser gases become (the more molecules are required to fill a given flexible space). Double the pressure (at 10m seawater) and it takes twice as much gas to fill your lungs with each breath. Triple the pressure (at 20m seawater) and it takes three times as much. Thus, the deeper you dive, the faster you consume air from your scuba tanks, no matter how much air it holds to start with. So how long does a scuba tank last? The average beginning diver’s air consumption in calm waters runs a tank close to empty in around 1 hour at 10m depth (compared to just a few minutes at…

Most divers use scuba tanks filled with simple compressed air (filtered and dehumidified). This is safe and standard within recreational diving limits – breathing other gasses or exceeding depth/time limits requires the use of specialised gas mixtures: primarily Nitrox, Trimix and oxygen. What is Nitrox? Nitrox, also known as ‘Enriched Air’, is a blended gas consisting of pure nitrogen and oxygen. The air we breathe normally is ~21% oxygen and ~79% nitrogen (with other trace gasses mixed in); Nitrox (generally) has an oxygen percentage between 22 and 40%. Recreationally, diving with Enriched Air Nitrox allows longer no-decompression limits (although it restricts maximum diving depth due to oxygen toxicity) by reducing the amount of nitrogen your body absorbs, thereby reducing relative risk of decompression sickness vs comparable dives using scuba tanks filled with air. Diving with Enriched Air Nitrox (EANx) requires special safety training, a scuba tank gas analyser and a scuba tank fill location with a compressor (and gas blender) capable of both producing and ascertaining the desired gas mixture. What is Trimix? Trimix is a mixture of 3 gases (nitrogen, oxygen and helium) used to increase depth limits and/or dive times. Whatever its percentages, this scuba tank gas mixture…