Nitrox and Compressed Air?

[Hostage]

I have yet to take the Nitrox Specialty yet, though I am wondering if people switch between the compressed and Nitrox in the same day. Do people that use Nitrox end up staying or do they go back and forth? It seems like Nitrox is 2 or 3 times more expensive than compressed air, which can matter if you are doing a lot of local diving. Though on the upside if you are on an expensive vacation, the Nitrox seems like it would allow you more diving. I am guessing one reason to switch would be for deeper depths.


I guess one worry of mine is forgetting to switch your computer to the correct mode.

-Hostage

 

[rhwestfall]

I have, and will use different mixes for different dives in the same day. part of my pre-dive routine is to verify the computer settings....

 

[windapp]

Air is EANx 21. Most computers require you to put in a mix for each dive after you switch to nitrox mode. You are not permitted to switch between modes. Mine operates on 79 nitrogen, and 50 percent oxygen if I forget. My dive will be short and shallow but I won't get injured.

 

[Rhone Man]

Some people switch between them on the same dive.

 

[rhwestfall]

Air is EANx 21. Most computers require you to put in a mix for each dive after you switch to nitrox mode. You are not permitted to switch between modes. Mine operates on 79 nitrogen, and 50 percent oxygen if I forget. My dive will be short and shallow but I won't get injured.

not sure of your use of the word: "most"

I have two computers (Cochran EMC20 & Mares Puck) - both allow me to switch mixes between dives. I do dive the Puck in "nitrox" mode, setting it to 21%. Also, i do not have to set the mix percentage each time on either.... YMMV.

 

[windapp]

I have two computers (Cochran EMC20 & Mares Puck) - both allow me to switch mixes between dives. I do dive the Puck in "nitrox" mode, setting it to 21%. Also, i do not have to set the mix percentage each time on either.... YMMV.

I said mode, not mix. My computer lets me set the mix to whatever it is, but won't let me switch back to "air" once in "nitrox" mode. If I dive air, I set it to 21%. A was led to believe by my instructor that most computers would at least give you the option of defaulting to a safe (albeit impossible) mix if you forgot to enter the new mix.

I guess that is a consideration when looking into dive computers if a lot of them don't have this option. I like the safe default personally.

To the OP: In any case, if you are diving nitrox, you never switch back to air mode. You simply set the mix to 21%.

 

[macado]

Depends on where you're diving, nitrox availability or your preference really. There is no right answer. If nitrox is an extra 10 bucks a tank, I might opt to use it for only one dive if I'm trying to save money. In places where nitrox is included for free or cheap, I would probably use it for all my dives.

I've occasionally only dove nitrox for particular dive to get a better no decompression limits (NDLs) and switched back to air on a 2nd dive or vice-versa. Sometimes people might dive nitrox for their last dive to help accelerate offgasing.

Keep in mind, some nitrox computers will default to 50% mix if you don't reset the mix after diving. This is done as a fault safe. You can turn this option off on a lot of computers. Always make sure to set the mix on your dive computer.

If you think about it this way, all dives are essentially nitrox dives. Air is 21% EANx.

 

[Damselfish]

yes, sometimes people switch on the same day for various reasons. One reason would be to save money, though if you're on an expensive trip someplace doing a bunch of dives every day, many people consider what you gain to be worth the extra bucks and people usually seem to just stick with it. Sometimes you can get a package that includes unlimited Nitrox, some places even offer free Nitrox, in which case there's no (financial) incentive to switch.

Could also be you're planning a dive that's too deep for the mix you can get. Or maybe you're at some resort that leaves out air tanks at night, but not Nitrox tanks unless you plan ahead or something. Just slightly less convenient to have to change your computer from time to time but really no big deal. It will become part of your routine.

 

[pasley]

I have yet to take the Nitrox Specialty yet,

Take the course and get your questions answered there.

though I am wondering if people switch between the compressed and Nitrox in the same day.

Yes, some do, depending on many factors and personal preferences.

Do people that use Nitrox end up staying or do they go back and forth?

Yes. Nitrox is used when it offers an advantage to do so. Advantages range from longer bottom time to less preceived fatique after a dive or when diving using air tables, increased margin of safety from DCS. With Nitrox comes Maximum Operating Depth (MOD) which limits your depth. Nitrox is not a gas for diving deeper, your depth is limited.

I guess one worry of mine is forgetting to switch your computer to the correct mode.

Which accounts for the necessity for a solid pre-dive check list and proper training.

 

[highdesert]

I am guessing one reason to switch would be for deeper depths. -Hostage

Only in the respect that Nitrox will allow you more bottom time at an allowable depth for a specific Nitrox blend. When you take a Nitrox course, you'll learn that there are very specific maximum depths for different Nitrox mixes. Where custom Nitrox blending is not available, you'll find that if you want to dive deeper (within your recreational diving limits), you may have to switch from standard Nitrox mixes back to conventional compressed air.