Diffusion stones work great for both carbonating and oxygenating. In order to carbonate in your cornelius keg, simply connect 2` of gas line into the gas in dip tube and attach the stone to the other end. Crank the C02 very slowly (about .5 a psi at a time. For Oxygenating, either attach the stone to an air pump, or even better, connect it to an actual oxygenation bottle.