Our guide to everything you need to know about the scuba tank
The origins of the diving tank
The scuba tank was invented in 1839 by James Elliot and Alexander McAvity of Saint John, New Brunswick.
Usually, a scuba tank is filled with high pressure air. However, it can contain a mixture (Nitrox, Heliair, Hydrox, etc.) in order to improve certain properties such as increasing attainable depths, shortening decompression stops or limiting the risks of decompression accidents.
What materials should I use for my scuba tank?
In most cases a diving block is made of steel or aluminum. However, it is possible to have a carbon diving block. Aluminum and carbon cylinders can be chosen to avoid the rusting phenomenon that can occur with a steel cylinder.
The dimensions of the different diving blocks
The volume of a standard scuba tank is usually between 4 and 20 liters (the most common are 12 and 15 liters). They usually have a working pressure of 150 bar, 200 bar, 232 bar (often rounded up to 230 bar) or 300 bar. These high pressures make it possible to store a large quantity of compressed air in the cylinders: 3000 L of air for a 15 L diving block with a working pressure of 200 bar.
Different types of valves
A diving cylinder is also equipped with a valve that allows to release the air contained in the cylinder. There are two types of valves: DIN and Stirrup.
DIN valves are usually used more in European countries, while stirrup valves are more common in North America.
To be able to breathe the air contained in the cylinder, it is necessary to equip it with a diving regulator. The regulator allows the diver to adapt the pressure contained in the tank to the ambient pressure in order to make the air breathable by the diver.
How to fill my scuba tank ?
To fill a scuba tank, you need a scuba compressor to reach such high pressures. There are different sizes of compressors that can be used to fill a diving tank more or less quickly. To have access to a diving compressor there are two solutions: the personal purchase or the paid filling of the cylinders in a diving center.
Depending on the size of the compressor, the purchase of a compressor can be very expensive. That's why most people prefer to fill their tanks in a dive center for only a few euros.
What maintenance for my scuba tank ?
In France, diving cylinders with a volume of more than 1 liter are subject to periodic requalification. This qualification must take place every 2 years, but it must also be accompanied by a regular control of the condition of the diving cylinder. In the European Union, diving cylinders are subject to the CE standard for manufacture and qualification.
What are the prices for my scuba tank ?
The purchase of a diving cylinder can be expensive because it is often accompanied by many accessories: regulators, hoses, pressure gauges, stabilized vest etc.
The total cost can therefore start at around 700 euros, if you choose entry-level products, but it can quickly reach several thousand euros if you choose high-end products.
If you want to start diving, you should therefore start with entry-level or mid-range products in order not to have too large an initial investment.
If the goal is to replace the snorkel in order to explore shallow aquatic environments, it would be better to go for mini tanks such as MiniDive. The purchase price will be less important and it will allow you to be more free and autonomous.
MiniDive tanks come in two different finishes: Aluminum and Carbon.
Their volume is between 0.2 L and 2 L for an autonomy ranging from 3 minutes to 40 minutes.
The first range of products for underwater exploration includes cylinders equipped with a hose and a diving regulator:
The aluminum cylinders, MiniDive Pro (0.5 L) and Pro+ (0.8 L) are dressed in a navy blue leatherette protection. These cylinders have been used since the beginning of MiniDive, more than 5 years ago.
They have a working pressure of 200 bars.
The carbon cylinders, MiniDive Carbon (0,5 L), Carbon+ (1,1 L) and Carbon Max (2 L) are protected by an epoxy finish.
Carbon cylinders are lighter and smaller (for comparable size) than aluminum cylinders. However, they can hold more air thanks to a higher working pressure of 300 bars.
All the cylinders are equipped with the same valve (DIN type) which makes them interchangeable.
MiniDive Carbon+ (1,1 L) + 220 V
It is therefore possible to use the regulators on both aluminum and carbon diving cylinders. This makes it possible to change an empty dive cylinder for a full one quickly and easily while keeping the same regulator.
It is also possible to use any diving regulator, as long as it is DIN type. This will allow you, if you already have diving equipment, to reuse your own regulator.
For those who wish to dive several times in a row, MiniDive also offers the possibility to buy the cylinder alone without having to buy a regulator.
The second range of products for discovery and safety includes very small cylinders with regulator heads:
These are new products recently launched in 2021.
These cylinders, very small and very light, are used directly in the mouth thanks to their regulator heads and provide a few minutes of autonomy. On average, 3 minutes for the 0.2 L aluminum bottle (about 700 g) and 5 minutes for the 0.35 L carbon bottle.
In order to be completely autonomous MiniDive offers 4 ways of filling their bottles:
- The manual pump: it is easy to use and can be used almost anywhere (does not require electricity). Very light and easy to carry, MiniDive advises its use for small volumes of diving cylinders (less than or equal to 0.5 L).
- Refill stations: they allow to refill MiniDive cylinders from a diving block. The station serves as a connection between the large dive cylinder and the MiniDive to transfer compressed air. In order to fit all diving cylinders, they are available in two models: DIN and bracket.
- The 12 V mini compressor: small and light (5 kg), it allows you to increase the pressure to 300 bars by simply pressing a button. Very easy to use, it can be powered by a 12 V battery (car or boat) or directly by a normal mains socket (220 V or 110 V) by taking the option with the converter. It is capable of filling cylinders with a volume of 0.2 L to 0.8 L.
- The 220 V (or 110 V depending on the model) compressor: powerful and robust, it is capable of filling any MiniDive cylinder quickly. Easily transportable thanks to its handle, it is possible to refill several cylinders in a row or a standard diving block by opting for its large filter cartridge.
You now have all the information you need to make the best choice for your needs.