Air Regulators & Tanks

     While underwater, you breathe either compressed air, or Nitrox (a mixture of nitrogen and oxygen). The gas comes in a 30 lb. aluminium cylindrical air tank, which can hold about 2,000 litres of air. The cylinder is fitted with a regulator to reduce air pressure. Direct pressure from the tank can seriously damage your lungs and respiratory system. For this reason, the regulator is designed to adjust the pressure until it is safe to inhale.

The regulator works in two stages:

1. The first stage attaches to the cylinder and reduces air pressure.
2. The second stage connects to the first with a hose. It further reduces the air pressure and directly supplies the air as you need it. The air is supplied in two modes; operational (only when you inhale), or emergency (continuous).

     Pony tanks are smaller cylinders strapped to the main tank. They have a separate regulator and air supply. These are used in emergencies, such as a rapid ascent from very deep water.

     Spare air units have a air regulator built right into the on/off valve of your buoyancy control device. These only contain enough air to ascend from shallow water.