The three cylinder diving pump.

By deciding what kind of air system we would chose we had two options; the first was a buffer with a reducer and the second was an original pump. Eventually we decided to use the diving pump and it was for several reasons. First of all, our goal was to dive "the old way" so that meant with original equipment. Secondly, the use of a pump gives the diver the characteristic sound of pressurised air coming in the helmet. Thirdly, we can keep more participants busy, after all, we have to supervise so others must use their muscles….

And at least, with a pump there’s no shortage of air. (Later participants told us that they have been diving at other diving schools where they used the buffer. Because there were so many participants the airflow was reduced to prevent that this diving school was running out of air. This resulted in a carbondioxide poisoning)