Scuba tanks should be a part of every diver's kit. While they contain no air, they do contain a large volume of free gas, which is generally greater than the amount of water they can hold. Tank sizes vary according to the type of diving you'll be doing, and you'll want to choose the right one based on the type of water you plan to go in. Below are the main types, as well as their sizes.
scuba tanks contain no air
The standard aluminum 80 can holds 77 feet3 air. Trimix, which is a type diving gas, has a 10 to 20% lower capacity than air. A higher maximum operating pressure doesn’t necessarily mean that there is more air. Manufacturers tend to overstate their tanks' capacity, though. Hence, you should compare the capacity of each cylinder against the actual volume of air in it.
They have more gas than water and contain more free gas.
Technical divers use mixed gases differently to recreational divers. Their true air and Trimix capacities, however, are lower than their actual water capacities. Because Helium is less compressible then air, the true air and trimix capacities of technical divers are smaller than their actual water capacities. Heliair 10/50, on the other hand, has a true volume of 216 ft3 and Double HP117 cylinders a volume of 235ft3. Use the Z Factors (SCUBA tables) to determine the correct mixed gasoline capacity.
They can be made from steel or aluminum
If you are faced with the choice between an aluminum and a steel scuba tank, make sure to consider what is best for your needs. Steel tanks can withstand deeper dives and are more durable. But, durability comes at a cost. Aluminum tanks can develop structural fractures more quickly and can be dangerous. A steel tank is more expensive than an aluminum tank. However, aluminum tanks have become the industry standard.
They are available in various sizes
Scuba tanks are made of two materials: steel and aluminum. Steel tanks are lighter and more durable, but tend to weigh more. An aluminum tank may be better if you plan to dive frequently and need to carry a weight belt. Aluminum tanks may not be as light as steel tanks so it is important to know your weight requirements before you purchase one. Steel tanks are excellent for drysuit diving as well as local scuba divers.
They should be inspected frequently
There are many options for checking your scuba diving tank. Hydrostatic testing is usually stamped into the metal beneath the neck of the tank. You can also inspect the tank visually to detect corrosion and contamination. Tumbling is another way to check the condition of your tank. Tumbling involves filling your tank with media, and then spinning it for a period of time to remove any dirt or other contaminants. If the tank's sound is unusual, it might be an indication that it needs to get cleaned.