Picked up a little catalytic propane heater the other day to take the chill off the cabin while working on her. It's a little Coleman unit that runs on the small propane cylinders like you use on a soldering torch. I had planned to get an adapter so I could hook it up to a large 5 gal bar-b-que sized tank, but while reading through the directions for the heater (yea, I do that once in a while!) I noticed that it specifically said not to use that sort of set-up. It didn't say why, it just said don't do it. So what I'm wondering is, is this just a ploy on their part to get you to buy outrageously expensive little propane tanks, or is there something different about the propane you buy in bulk that would hurt a catalytic heater? The heater only runs for about 5 hours on the small tanks, and at $2-3 each it's a bit expensive, not to mention inconvienant to keep a bunch of the little tanks around. Anybody know about this stuff?Thanks,Jeff