W W Meixner
Banned
Just for consideration, you get the "oily" fill. Wouldn't the most dangerous PP fill be the next one?
BRT...
Unfortunately...you never know when and where the bad fill came from as you're not inspecting your tanks after each fill...not inspecting your tanks for five years who knows how much hydrocarbon may have been introduced...sometimes during inspection the odor is detectable...sometimes it isn't...
Shops doing a lot of exotic gas fills usually have a ''hyper filtration'' system installed to help prevent this...
Some shops are now abandoning PP fills in favor of ''fill blend stick'' systems...and are not requiring the tanks to be O2 cleaned unless the NITROX fills are over 40%...
The more often your tank is inspected...and thoroughly cleaned...the cleaner it will be...both inside...and out...
Frequent inspection is also important for steel tanks in the event moisture...mostly resulting from condensation is introduced into the cylinder...
Condensation in steel tanks here in Canada is a concern as a lot of divers store their tanks in unheated boat houses...that are often -20 in the winter...interior condensation drips to the tank bottoms causing rust pitting...leaving a debris plugged tank boot on for five years without reasonable frequency tank bottom inspection is another problem...as is corrosion building up behind tank stickers...
There is science and reasoning behind annual inspection of scuba cylinders...and there are pros and cons to extending service frequency...if this standard is adopted in North America...which may be unlikely...I can see a lot of shops failing cylinders for detected problems that have deteriorated beyond acceptable levels because the cylinders haven't been inspected for five years...and you know individual tank owners are not going to do much ''preventative maintenance''..
Dive Safe...
Warren