How often do most shops in your area require Nitrox tanks to be O2 cleaned?

[In10se]

richherso I know you asked Joanna, but the research I did before I chose to do nitrox was based partly on what I've studied from this site so I'm sharing the link with you anyway. After you read the answer you can scroll up to the index that covers your question and then some.

One of the enticements was:

"On nitrox60 (40% O2) the EAD = 45 fsw (13.5 msw), so we use the 50 fsw (15 msw) table. The NDL is 75 mins."

 

[JessH]

So, what's the 'practical' advantage to Nitrox? What profiles should I be diving that will really exemplify a need for Nitrox? That's my question.

Well when you start diving a little deeper or want to do more dives in a day you might see the benefit of the decreased nitrogen loading. If you find that your current dive profiles do not require it then the benefit would simply be a decreased risk of getting bent.

~Jess

 

[JessH]

\
1) What was the original question? Something about frequency of O2 cleaning a tank? I still don't know the answer. I apologize to anyone who actually answered this question. I haven't read the first 8 pages of this thread. Sorry.

Don't feel bad about not reading the first 8 pages, the question was what the policies of shops were regarding frequency of O2 cleaning, not what they should be. No one has answered that question.

2) It sounds like Austin doesn't have a "tech" shop in the area. I am not going to bad mouth anyone here or promote anyone here (trying to remain, at least somewhat, neutral) but Arlington does have a tech shop that banks 32 and 36 EAN.

Unfortunately the closest thing we had to a tech shop closed for political reasons so now other shops are trying to fill their shoes. Oak hill scuba seems to be doing a decent job but they are so far south that it it inconvenient for some such as myself. Unfortunately as far as I know no one here is banking Nitrox but I am not going all the way to Arlington to get it.

~Jess

 

[JessH]

Hey Mack, most people here seem to think the problem is that no one in Austin banks Nitrox. You want to start banking EAN32? It is even a great start for mixing most standard trimix fills If you start banking 32 I will start making the commute to your shop.

~Jess

 

[scubashawn123]

So if I want a nitrox fill anywhere other than my local shop I need to pay for an O2 cleaning first? (We have already established a viz is not sufficient)

How many traveling divers will pay $60 for a fill?

EDIT: Maybe shops should just bank nitrox so they can fill any tank or just not bother with it?

Exactly my point days ago. Most shops east and west coast do bank Nitrox so that an O2 cleaning is not necessary for 32/34/36 mixes. Most of them, and a lot of dive boats bank 32, pay a couple bucks extra, usually $10 a fill and have the Nitrox available on your dive.

Maybe this would be to easy, since it requires only the same level of effort as getting 21% Air.

Right now it requires 2 trips and a week or more to get Nitrox in this town.

All the benefits of diving Nitrox become logistically to complex and labor intensive to really use in the local dive scene.


Shawn O'Shea

 

[Joanna.Cordry]

Joanna,
Please help me out here. I am just curious. btw, I am nitrox certified.
I am still trying to figure out why I would ever want to dive some EANx mix. Now mind you, I am not tech tri-mix certified so I am not talking about deco stops or travel gasses or anything like that. I am talking about a single Al-80 strapped to my back for one complete dive.

I know what the theory says. Reduced N2 loading, etc, etc, etc means "faster" off-gassing on the surface which translates to quicker surface intervals before the next dive. Theory also says increased O2 content means somewhat restricted bottom depth. Maybe that's a problem; maybe that's not.

The problem I have is this: I don't think I have ever been a on dive excursion (CSSP, Travis, Cozumel, Bonaire, etc) where I said "Dang! Had I been diving Nitrox I could grab that next boat dive in 5 minutes. No I can't do that. I have to off-gas for another 20 minutes." I have never once had that incident be a restriction to my diving activities. Go figure. So, what's the 'practical' advantage to Nitrox? What profiles should I be diving that will really exemplify a need for Nitrox? That's my question.

I really like nitrox when I'm on a liveaboard - especially some place like the Flower Gardens - or when I go to Florida, or somewhere else where I'm doing multiple dives a day in the 80-100 range over multiple days. I use it in those situations NOT so that I can decrease my surface interval nor so I can stretch my dives out longer; I use it because, on air, the build up of nitrogen in my system makes... me... zzzzzzzzzzzzzzzzzz... <konk>. Plus, I think I'm more clear-headed at 95 feet on EAN32 or EAN36 than on air.

Something I find interesting: the more I read about and/or listen to very experienced divers, the more I realize how the physiology of one person can be very different from that of another. I've met people who have taken a DCS hit when no one in their right mind would have predicted it; I've met people who regularly push their PPO2 WAY over normally accepted limits and seem to be fine; and I've read about people who were thought to have seized from O2 toxicity when one would never have expected it based on their gas plan (I put that in the "freak incident" category). Also, even though gas models are theories based on "the average human," different models will suggest different profiles on the same mix. It's not just the mix that is going to dictate your limits - it's also what tables/software/computer you're using, how well you follow the plan it gives you, and your individual body.

I listen to people who thousands upon thousands of dives, especially when they gained that experience in different environments and over decades. I also try to stay current on and understand theory as best I can. However, IMO, there is no substitute for experience that is gained by slowly/methodically exploring how you individually react to different situations/gasses/etc.

 

[Joanna.Cordry]

Don't feel bad about not reading the first 8 pages, the question was what the policies of shops were regarding frequency of O2 cleaning, not what they should be. No one has answered that question.

My experience has been that the dive shops I have been to in Austin have required tanks to be O2 cleaned every year b/f they will put Nitrox in them... well, at least 3 of them - the fourth, I may have just assumed it (Mack - does Oak Hill require cleaning every year?). I haven't had my tanks filled at any others.

 

[paul19may]

"On nitrox60 (40% O2)FONT]

Priceless.

 

[richerso]

Kewl! Thanks all. Kudos to you Joanna.
I was just wondering.
btw, I tend to agree with you on the zzzzzzzz, <konk> thing. Tends to happen to me too after a few days of diving.

 

[Mack Diver]

Hey Mack, most people here seem to think the problem is that no one in Austin banks Nitrox. You want to start banking EAN32? It is even a great start for mixing most standard trimix fills If you start banking 32 I will start making the commute to your shop.

~Jess

For the record, I am ready willing and able to bank 32 mix. All I need are the HP bank cylinders to store it in. Those boogers are pricey! If I could get my hands on 4 - 6 of them cheap, I would certainly invest the rest of the $$$ to make the setup happen.

For Nitrox fills, we do not require an overnight wait. We can usually fill your tanks on the spot. Granted, because of the partial pressure blending process, the fill takes longer than an air fill. However, its not like it takes hours or anything. I have several customers come in and get their tanks filled while they wait.

As far as O2 cleaning goes, we charge a slight premium to VIP a nitrox tank. That covers the cost to clean the tank. We do not require an annual rebuild on the valve. So far, our policy has not burned us, pardon the pun.

When it comes to contamination from regular compressed air fills, I think it depends on where you get your fills. When this thread started taking off, I check the latest test report on my fill station. Total gaseous hydrocarbons were 3.3 ppm, with a specification limit of 25 ppm. I doubt all 3.3 would adhere to the tank on each fill, so I'm not sure how many fills it would take to reach a critical level. Too much math for my little brain.