Ok, so you O2 clean my tanks, then fill them. I then go diving for the next two months and fill my tanks with regular air from my home compressor. I tend to be suicidal though so I use a gas compressor, with no venting and just use an old oily rag as my intake filter. Now I decide to bring my tanks back to you because I want some good ole O2. You cleaned them, but you have no idea what I put in them.
The sticker tells you when it was O2 cleaned and regardless of whether you put the sticker on it yesterday or another shop did 6 months ago, you still have no idea what has been put into once it leaves your sight.
This sounds like a perfect example of LDSs "give me money" line.
You know, if I had to pump pure oxygen into someone's tank, I would want to O2 clean it myself. OK, so it was cleaned, way back when. How do I, a simple tank monkey, know that you haven't polluted the tank with crappy air after is was cleaned?
It's odd, LDSs are willing to accept the 'Nitrox Clean' from tank manufacturers before doing partial pressure blending. But that's not what the tank manufacturer said. They said the tank was clean for EAN40, not pure O2. I have always wondered about that...
here are two statements i read in another post, and belive it should be cleared up and explained.
i might be off on this just a bit, so i will ask Gilldiver and Luis H to chime in and correct me where i am off, but here it goes
Quote 1
your right, we dont know what went in the tank. but if you are not using your tank strickly for nitrox use, the sticker has to be pulled off the tank.
the shop should ask you if it has had anything but nitrox put in the tank ( and since people dont allways tell you the truth ) and analyise the contents off the tank to be sure. if it does not have a certain percentage of 02 ( it think is 23 % but this is where i might need the correction, i dont have the book with me to check ) the sticker needs to be removed because you have changed the contents of the tank. this is a CGA or DOT ( one or the other ) rule.
as far as the fact that you are using your home compressor, if the air you produce is not modified grade E, is is not sutiable for use with oxygen and should not be used for paritial pressure blending.
Quote 2
as i talked about in the first quote, you should be checking the 02 content of the tank. this should be part of fill station operator training at a shop to help inform you ( the filler ) of these questions.
as for the nitrox clean from the factory, i believe the word you should of used is "compatiable". the tanks are good for use with 40% or less nitrox mixtures, but only if fillede from a bank system filled with premix 40% or less mixtures, or a membrane system. if you are going to put 02 in the tank it should be cleaned first.
hope this clears up some questions people might have reguarding this subject, and as i said before, i might be off a little in these expliantions and would like to be corrected anywhere i am wrong.