- Greater need for the diver to observe his depth limits at all times.
- Increased risk of oxygen related problems
- The need to analyze your breathing mix and know your PPO2 at all times.
- More steps in dive planning
- Additional cost

Yes, the use of nitrox is not difficult but you must now track your Oxygen exposure using additional means such as charts or a computer. It requires some extra planning.

It is acceptable as it comes from the manufacture for use up to 40%.

No, regular dive tables work fine you may do the EAD calculation or use a pre made set for the mix you chose.

No, it has no heat retention benefit.

It depends on if you accept oxygen as a narcotic, if not more so than nitrogen. Different agencies and experts still debate this issue to this day. Studies show that the mechanism believed to causes narcosis is related to the induced compounds molecular configuration. If this is true, and we believe it is, Oxygen IS a narcotic gas, perhaps even more so than nitrogen. There will be no reduction in narcosis. If you do not accept Oxygen as a narcotic, then the calculation will show a reduced level of narcotic gas.

You may. Many divers claim they are not as tired and Òfeel betterÓ after using nitrox. This has nothing to do with nitrox. It is most likely the result of the lack of sub clinical DCS they normally have. Sub clinical DCS is DCS that is present but is not serious enough to warrant recompression. When we dive even within the limits of our tables, bubbles are present in our bodies. This is proven through Doppler studies. They are some times referred to as ÒSilent bubblesÓ. The average recreational diver surfaces way too fast. This can be seen on any dive boat you go out on. The 60ft Ð min is a maximum. In the original studies on which most modern tables are based 30 ft Ð min was max. Combine this with several other elements (ie. extra ascents, and the saw tooth profile done by most recreation divers, lack proper rest, dehydration, lack of general fitness and/or the absence of safety stops) and you get bubble growth resulting in subclinical DCS. This has been confirmed in a variety of studies form different organizations. Symptoms usually include fatigue, soreness and minor aches and pains. The average diver since the diver is not as close to the NDL and does not have the gas consumption rate to get close to the limits of 36%. Therefore, he has a better chance to get away with the above mentioned errors and remain symptom free.

Maybe, if you dive Nitrox using the air tables or the air setting on your computer. Yes, from a decompression standpoint because you will have less nitrogen saturation for a given time period. When using a computer set for air, it will not properly monitor your O2 clock, nor will its depth warning sound at the correct depth. It will display a shorter NDL than actual and cause the diver to surface with more of a safety factor. One should recognize that most divers are driven from the water do to lack of breathing gas, not lack of time so it does make the average diver safer from an over all perspective. The diver must know how deep he can go with whatever mix he is breathing and properly monitor depth at all times.

It is your life! If they made a mistake YOU will be the one to pay if the guy making $6/hr got distracted. You must know exactly what youÕre breathing. How deep you can go with it and how long you can breathe it? In order to do this you MUST be 100% sure of what you have.