> >Strangely enough - and wandering slightly off track - it used to be
common
> >place to crack a filled cylinder and sniff the air in order to detect any
> >obvious impurities.  That's something that seems to have gone by the by.
> My mate John (the same nut-case who managed to convince the crowd of
> youngsters they could water-ski off the back of a dive boat) regularly
> cracks the valve & pronounces, 'yup, smells like air'!
> Cheers....
>
and the last time I sat thru a PADI OW lecture, it was still  part of the
lecture.  Crack the valve and sniff the air.

CH