I have just built a keezer and about to hook up my CO2 tank, regulator, distributor and gas lines. I have an IPA that I am fermenting in the keezer and was planning to dry hop. I have not purged head space in the past but would like to do so now to prevent oxidation. How do you do so with a basic CO2 setup? Do I just turn on gas, regulator and open one distributor gas line and put in my big mouth bubbler? At what PSI? Ive tried to look up videos on youtube but most are not informative.