MikeFerrara:
Right...and out of the 1% of the population, how many are going to build an analyzer. You're kidding right? We are better off using the sticker. LOL
Buy it, build it, your choice. Sheesh - its a frapping voltmeter and a fuel cell for crying out loud!
You're right. Many shops don't analyze "air" tanks. Now days all tanks should probably be analyzed especially with people willing to put nitrox in tanks that aren't marked for them.
You just fixed it so no one needs to buy the dumb sticker but instead needs an analyzer. Way to byte your nose off to spite your face. LOL
Not.
First, I don't need the analyzer. The shop does. If I trust them not to pump oil into my tank I might trust them to analyze an AIR tank (maybe - I like it better if they either do it in front of me or I do it though.) And they do need one irrespective of what they pump, unless they're prepared to dump every tank that comes back in from rental.
It only takes ONCE to kill someone. One time that some guy rents a tank, takes it home, decants some O2 into it, intends to take it to a remote dive location and have it "topped off" (without telling anyone of course.)
Then the dive is called before he gets there and he hands the tank back in without remembering what he did.
Now the shop has a literal CNS bomb sitting there, which they unknowingly top off and hand to an unsuspecting diver, and neither of them is the wiser because nobody bothered to check.
Can't happen? Oh yes it can!
Someone takes that "CNS bomb" to the bottom of a quarry at 120' and.....
If you're going to play the "no sticker = air" game then you have to implement the controls to insure that nothing other than air is in the tank. This means that (1) you cannot pump anything other than air - no nitrox on facility at all - and (2) you must DUMP all tanks that come back in from rental, irrespective of what someone tells you or how much pressure is in them, in order to INSURE that the only gas in there is the gas YOU put in there.
Without that level of control you're fooling yourself if you are
sure that there's only air in that scuba tank.
(BTW, I use "painters tape". It stays on plenty fine and is easy to write on with a nice sharpie marker, but doesn't leave sticky crap all over my tank when I pull it off.)