There are two basic types of tanks; Steel and Aluminum, while there are benifits for both, when considering diving in Sydney steel tanks provide better comfort in the water as they are much smaller (better mobility) and heaver (less weight in you weightbelt) for volume. With good care Steel will last 10 years.

While each person is different and air consumption improves with experience, as a guide, tank capicity as follows; 9L or 75cf for small men and most women, 10.5L or 85cf for the average person, 12L or 100cf for men 90kg + While there are small and larger tanks avaiable this is a basic guide.