what is in divers tanks mixtures
The majority of gas used in most SCUBA tanks is compressed air. This air is composed of the same elements everywhere - 21% Oxygen 79% Nitrogen. Advanced SCUBA divers may use an enhanced mixture of 32% (up to about 40%) Oxygen with the balance being Nitrogen. The number of divers who use a mixture like this is about 2 to 5% of all certified divers.