80 CF Vs. 100 CF SCUBA Dive Tanks

Scuba tanks come with a range of capacities. The most popular capacities are between 80 cubic feet and 100 cubic feet, with the average tank holding 80 cubic feet. Several factors affect which cylinder capacity is most suitable for the individual, including the diver's physical condition, the weight required and what the diver will be using the tank for.

  1. Definition

    • All tanks, regardless of their capacity, will be filled to 3,000 pounds per square inch. The classification of the tank capacity is how much air can be stored in the tank when it is pressurize to 3,000 psi. So at this pressure, an 80 cubic foot tank holds 80 cubic feet of air, which is equivalent to the size of a telephone booth.

    Gas Consumption

    • The amount of gas a diver is going to use is the most important factor in selecting the capacity of the tank. The amount of air you will need is determined by the size of your lungs, your fitness level, your size and other factors. These determine your gas consumption levels. If your gas consumption is becoming a limiting factor on your bottom time, then the larger tank would be a better selection.

    Weight

    • The weight of the tank is a major consideration for a number of divers, who balk at the suggestion of carrying a larger tank. This factor, although it does not take into account air consumption, would suggest that an 80 cubic foot cylinder would be more suitable for the diver's needs.

    Breathing Gas

    • If a diver is using a gas such as enriched air nitrox with the aim of extending bottom time, he will tend to stay down longer. Nitrox divers push to the limits a little more, and would be happier with the larger 100 cubic foot tank because they are looking to be underwater for as long as possible. This factor is also affected by gas consumption because pushing the limits is not possible if the diver's consumption is too much.

    Dive Environment

    • The area where the diver will be using the tank also affects the choice of the tank. If the diver is to be submerged in a swimming pool with little movement or depth, then an 80 cubic foot tank would be suitable. However, if the diver is doing a deep dive in harsher conditions, then she might find that she would want more capacity in her tank as gas consumption increases with depth. Local conditions, such as currents and water temperature, also can factor into the diver's choice of tank.