Oxygen cleaning for nitrox tanks - how often?

[CDNScubaMoose]

I hesitate to ask this question since I have a sinking feeling that I may have been had by a local dive store. I noticed this topic on another board that doesn't get the same amount of traffic as this one and was amazed by the responses so I am curious if this is true.

I know that I need to get my tanks oxygen cleaned before I can get them filled with nitrox (at least if I am getting them filled using the partial blending technique). But what I am now curious about is how often I need to get them cleaned. I was under the impression that I had to get them cleaned this way once a year and I was combining it with the VIP. It was expensive to get 3 tanks (and now thinking maybe up to 5 tanks) once a year but the benefits I was getting from the nitrox made sense to me. The LDS I normally go to does not do nitrox fills nor oxygen cleaning so for this requirement I have gone to another LDS for the last 3 years. From the other board I now have heard that provided that you only get your tanks filled with nitrox or from a properly filtered air station that there should be no need to get the tanks oxygen cleaned every year. Basically as long as I don't contaminate them or let them completely drain then a simple VIP each year should suffice.

When I took my nitrox course the instructor only mentioned that tanks needed to be oxygen cleaned and I assumed that it meant every year. The LDS in question never mentioned anything (but why would they - they are getting business that otherwise they normally wouldn't) and my normal LDS isn't that familar with nitrox (in fact the store owner has sent his nitrox tanks with me to the other store for the last two years to get cleaned as well). The explanation of why I would only need to get them cleaned once makes sense but at the same time I would like some confirmation on this.

Thanks

 

[sharkattack]

Once a year with VIP. Valves should be serviced along with regs. When done, they are O2 serviced as well. Good cleaning, Fresh O-rings, Crystal lubed. It's not a long hard process.

 

[CDNScubaMoose]

Thanks sharkattack - That was the impression I was under but when you mentioned getting the valves done as well as new o-rings, that made sense to me. Good to know that I wasn't wasting my money.

 

[sharkattack]

No problem. Anytime.

 

[Divin'Papaw]

I also have mine done once a year at the same time as the VIP.

 

[do it easy]

Some people are willing to take bigger risks than others.

I O2 clean my tanks every year, including replacing the seats, o-rings and burst disks. I spend about $200 on parts alone to service my 8 tanks.

The first rule of gas blending is don't blow yourself up!

 

[mike_s]

You'll find many different opinions on this.

Some folks think it's not required again after the initial o2 cleaning.

some folks think "every year".


My thought is that every year is a good practice, but isn't required if you aren't getting that many fills and know your fill source as reliable and clean.


Every time you get a fill there is a likelyness that a little of some hydrocarbon might get in your tank. if you get 100 fills per year the chances are more than someone who gets less fills. however, it also has to do with how clean is the fill source you're getting it from.


What I'd like to see is some dive shops reply to this thread and give their answer and state "why" they require o2 cleaning every year.

 

[fisheyeview]

I clean them every year, or if I get a fill that was not through a clean whip.

If you are not doing partial pressure fills, and are just diving Nitrox I or II, then technically you do not need to have them O2 cleaned. I would still have them O2 cleaned though. Better to be safe than sorry.

 

[DeepSeaExplorer]

I get mine once a year whether they need it or not. Interesting that everytime I go to a different shop, they tell me that the last shop didn't 02 clean them.

 

[in_cavediver]

I'm different. I watch the fills more than the time. Its all about buildup of contamination right? I will never clean my o2 bottles again. They ONLY see 02. My 50/50, gets is every couple years. It gets light usage and see's few fills. My doubles, well, they get it when I plan to do serious diving. The bulk of the time is premix or air and lots of time to build up contaminants.

My nitrox/trimix tanks, They get cleaned every year or two depending on usage. If I plan to do serious diving with them, I'll clean them before diving.

My opinion, log number of fills and relative cleanliness. Then judge when to clean. Err on the side of caution and do it yourself. Then, its only your time that it costs.

I'd also say personally, I am much more concerned with the valve/manifold than the tank itself. The valve is where the constrictions and bends are and where soft materials are found. This is where I am the most concerned for combustion.