That would be in Pittsburg. What was known as ADT aka Advanced Dive Training. They closed their shop, but still do fills for people. You drop your tanks off to a gym, and pick them up from there too. They bank 36%, and can blend anything you want. When we are in Monterey we always fill our tanks at Aquarius on Del Monte. They bank 32%. There are a couple of shops in the San Jose area also.
Either way it makes sense to get nitrox certified, for occasions when you can get nitrox. The bands on the tanks and O2 cleaning are not the way to go. Often places will not fill them with air if the tank has nitrox bands on them. The bands can cause the tank to corrode. Without o2 cleaning safety requires either continues blending or banked. Few do partial pressure blending in volume anyhow to require O2 cleaning.
Seems few dive shops see a profit in selling $10 per HP tank fills. Their cost per tank is not that great. Somewhere around $2.80 a tank, plus labor. Still profitable in volume.
