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View Full Version : Air or Nitrox??



Divemore
07-13-2007, 21:45
I am new to diving, I live in florida and I have bought all my equipment I have 2 tanks and I just made one tank nitrox. Now what tanks do other people have? It seems to only have nitrox tanks It is better all around right? Only to dive nitrox. I just cert in nitrox and It seems the best. So I should change both tanks?
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<DIV>Please explain to me.</DIV>
<DIV>Thanks http://www.scubatoys.com/forum/smileys/smiley9.gif</DIV>

FishFood
07-13-2007, 21:52
Man, if I only dove Nitrox Id be eating spam. Unless you NEED the extra o2 EVERY dive Id keep one tank air and save the money.
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<DIV>Just my 2 cents anyway... You know your budget better than I do. </DIV>

Divemore
07-13-2007, 21:59
So price for fills is the only down fall? Maybe I dont dive enought to care about fill price? Just compleating the nitrox class it seems like so much pros no cons..
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<DIV>I dont know, I only have 3 dives total and none with nitrox yet...</DIV>
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<DIV>http://www.scubatoys.com/forum/smileys/smiley9.gifhttp://www.scubatoys.com/forum/smileys/smiley9.gifhttp://www.scubatoys.com/forum/smileys/smiley9.gif</DIV>

TxHockeyGuy
07-13-2007, 22:05
Nitrox certainly has it's place but on some dives it may give you very little benefit. If you are no where near pushing the air tables, which is quite likely if you only have 3 dives, then you are already diving very conservatively. If you add Nitrox you will be diving very very conservatively. Is that really necessary? Even if the cost isn't that much I don't like throwing money away. I am nitrox certified myself and have only dove 2 dives on Nitrox, and those were required for the certification (dives are no longer required for certification today). That being said on this upcoming trip I am considering diving Nitrox on at least one of the days where I might be pushing up closer to the table limits. The other days I am already certain I'll be nowhere near my table/computer limits.

Divemore
07-13-2007, 22:14
But with that said your bottom time is longer all the way around so why not? Im so new that maybe I dont know what im talking about lol....
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<DIV>I dont want to throw money away eather but if I can watch that seahorse longer than thats worth it. You knowwhatI mean? http://www.scubatoys.com/forum/smileys/smiley2.gif</DIV>

TxHockeyGuy
07-13-2007, 22:29
I don't think you're understanding what I'm saying. Two things determine your bottom time, your NDL (No Decompression Limits, aka your tables) and your air consumption (how fast you drain the tank).

I can only go down to 60' for a max of about 45 minutes before I run out of air, this number would not change if I was diving Nitrox. Air tables allow a 55 minute NDL and EAN32 allows for a 100 minute NDL. So in this case there is no benefit to diving EAN32 for me except for diving more conservatively (extra safety). Personally I think surfacing with 10 minutes of NDL is already pretty conservative so I see no benefit for Nitrox for this dive. However, if I am doing multiple dives on this day then subsequent dives may benefit either by giving me an extended bottom time or if I am getting close to the air NDL by giving me an extra safety margin. Remember you either get an extra safety margin or additional bottom time, you do not get both.

For fun since you've taken the Nitrox class do a couple of simulated dive profiles running the tables based on your air consumption and see where you stand.

FishFood
07-13-2007, 22:31
But with that said your bottom time is longer all the way around
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<DIV>Your bottom time is only longer IF your approaching your no-deco limits. Right now, you're probably not going to be approaching these limits, and instead surfacing because you're out of air. </DIV>
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What is your air consumption like now? </DIV>

Divemore
07-13-2007, 23:05
What is your air consumption like now?
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<DIV></DIV>I dont realy know I think good. I am a female andtiny wt 115lbs 4'11'' I dont know if that makes a diffrence?

TxHockeyGuy
07-13-2007, 23:16
What is your air consumption like now?
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<div></div>I dont realy know I think good. I am a female andtiny wt 115lbs 4'11'' I dont know if that makes a diffrence?

It does make a difference. Females generally have better air consumption than males. Smaller people generally have better air consumption than larger people. That being said people who have just started diving generally do not have a very good air consumption rate. I have also seen exceptions to every one of these generalities so you really need to determine your own air consumption rate. During OW they should have had you writing down how much air you had at the beginning and end of your dive, your max depth, and how long you were down for. These will give you a good indication as to what your air consumption rate is. For example I managed to suck an al80 dry in just over 20 minutes on one of my OW dives at about 18 ft. Now I can make that tank last over an hour around 30', if it is a nice relaxing dive. It depends on so many things.

Divemore
07-13-2007, 23:25
Ow class said they were going to do that,so that should be helpful for me well you are right I should dive more and keep one tank for air and one nitrox. thank you. i think you and i are the only ones up at this time and on this site lol.
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<DIV>Thank you...http://www.scubatoys.com/forum/smileys/smiley2.gif</DIV>

cummings66
07-14-2007, 11:34
Tell us how about your average dive, how long does it last and what do you think the average depth of it is?
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<DIV>I gave you in another thread the tools to calculate your air consumption, might try it and see what yours is.</DIV>

frankc420
07-14-2007, 11:47
It really depends, are you going deep enough and wanting to stay down long enough to justify using nitrox? Regardless, if you get both tanks cleaned and you put the super duper Nitrox sticker on your tank, by all means you can still dive a 21% nitrox (which is air, btw).

gangrel441
07-14-2007, 16:52
I would add that that for multiple days of multiple repetative dives, Nitrox does provide a benefit. If you are diving to Nitrox tables, your will run less chance on the repetative dives of bumping up against the table limits. If you do a week of 4-5 dives per day, believe me, it will make a difference.

plot
07-14-2007, 18:48
Depending on the type of diving you're doing, you can only go so deep with nitrox (109' or something like that? depending on the tables you use anyways)... air can get you down alot farthur.
<DIV>Air is also cheaper, and chances are you'll run out of gas before you run out of bottom time... especially if you're only doing a few dives in a weekend.</DIV>
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<DIV>On the other hand... people often claim to feel energized instead of tired after diving nitrox...</DIV>

cummings66
07-14-2007, 19:37
You can dive Nitrox much deeper than that. I've done it to 127 feet. It depends on your mix.

jacewindu
07-14-2007, 22:14
my next step is nitrox cert. should be fun

woody
07-15-2007, 03:55
You can dive Nitrox much deeper than that. I've done it to 127 feet. It depends on your mix. <?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

And the associated risk that you are willing to take. Which approach do you take the conservative one of a 1.4 PO2 Max or the more aggressive one of a 1.6 PO2 Max.

Thanks
Woody

Mooosse
07-15-2007, 08:01
I am a new Diver myself (4 dives logged) and have not seen too much "AIR" tanks being used either - everything is NITROX.. I will be Nitrox Cert next week, but will still keep the AIR tank for general diving. As far as the price of the fills, each place I have gone in the ABC's is FREE NIITROX FILLS, so that should not even be a consideration - if you are looking for some bottom time just to gain the experience, then yes go with the air and call it a day...
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cummings66
07-15-2007, 08:15
You can dive Nitrox much deeper than that. I've done it to 127 feet. It depends on your mix. <?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><O:P></O:P>

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<DIV>I limit myself to 1.4. That means a pretty light mix, might as well call it air for all the good it does. Normally it's after a Nitrox dive and I get the tank topped with Nitrox Compatible air. Then I'll have a pretty weak mix but still technically nitrox.</DIV>
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<DIV>I'm not one to push anything, I want to live to be old and see my daughter graduate and marry. That's why my technical diving will not be more more than deep diving to see the outside of wrecks, no penetration until afterwards.</DIV>

cummings66
07-15-2007, 21:12
Nope, in my class that put the fear into you, the book even put it on bold print that if you tox you most likely will die as a result.
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<DIV>I know deco divers do higher numbers on occasions as well, but they don't do much at the deco stop other than hang there. Pretty sedate.</DIV>