Q: Who should use Nitrox?
A: Every diver.
Enriched air Nitrox or just Nitrox, is oxygen enriched air. That means that instead of the normal 21% oxygen and 79% nitrogen, the contents of oxygen has been added to maximum 40%. And while this limits the extreme depth that the gas can be safely operated on, it will extend the allowable bottom times drastically, especially near 20 meters and deeper.
As an example the no decompression limit with air at 18 meters depth is 56 minutes (as every certified divers will remember from the OWD course) but using Nitrox 36% the no-decompression limit at that same 18 meters is 125 minutes.
You can use the the Nitrox also to increase the safety margins, since the Nitrox will not accumulate the nitrogen load in diver’s body the same way normal pressurized air does. This course certifies you to use enriched air up to 40% oxygen in recreational diving within your certification limits.