For those of you who use pure O2, do you just use the 1.4 oz oxygen bottles from Home Depot? Does anyone use oxygen from the welding supply store? I can buy a 20 pound tank of O2 from Airgas for $10-12. This beats the heck out of $10-12 for 1.4 oz. if I go this route, do I just need a regulator with a hose barb, some hose, and an oxygen stone?