How I O2 inject I use a Stainless Steel "Carbonator Stone" which has 2 micron holes attached to a supply of welding oxygen from my torch. I ferment in soda kegs, so the stone is suspended from the lid of the keg with about 18" of beverage tubing so that it is on the bottom of the keg. Plans for fitting the appropriate bulkhead fitting are given in excruciating detail in my article on building an "oxygenator lid" in the Sep/Oct 1995 issue of Brewing Techniques. I will not type them in again here, buy the issue. In my article, I told very little about use of the stone, but I thought it was enough. I will basically state that again here because it is very short. 1) Decide how much O2 pressure you ultimately want in the keg (I use 20 psi) 2) Attach the lid with stone to the keg and attach O2 supply to the QD fitting on the lid. 3) Put your ear against the keg and very slowly turn the regulator valve until gas just barely begins to flow. 4) Wait until it stops flowing and then crack the reg. valve open another 1-3 psi until gas just begins to flow. 5) Repeat steps 3 and 4 in the smallest possible increments until the pressure you want has been reached. The very small increments allows the gas to flow into the keg for the longest possible time and give the bubbles time to dissolve. 6) Remove the O2 supply hose and let the keg sit pressurized for at least 2 hours to allow the O2 to dissolve completely. 7) Remove the "oxygenator lid" and stone and replace with a sanitized regular lid, put on your normal blowoff hose and begin fermentation. If you do not ferment in kegs, then I can be of no help on how to use a stone, I only ferment in soda kegs and my methods will not work on carboys.