Give US Cylinder Services a call...they were able to hydro my tanks while I waited the day before SG 45!
1204 W 17th St, Vancouver, WA 98660
You gas up the marker, put on the mask, and walk onto the field. It doesn't matter that you failed a test, your girlfriend broke up with you the night before, or that you just had a bad day at work. This is your heaven on earth. Live it and play it as if there was no tomorrow.
I would always look at the fire supply or welding supply stores. They work with the firefighters fiber wrapped air tanks and are more familiar with different style of compressed gas tanks. The fact that they charge you half as much as taking your tanks to a dive shop plays a part in it as well.