I am using two fermzilla all rounders 15g and three corny kegs to store co2. I made an inline spunding valve with gas poppets on either end. This way all O2 is consumed by fermenting beer. Co2 sounds like a jet stove for past three days, I had no idea beer makes this much co2. I could purge 100 kegs. My question is how many times should I pull keg post to purge each keg at 20psi. Do I even need to purge? The O2 should all be absorbed via diffusion by the fermenting beer within x hours? I now have three kegs at 20psi so I can use them to push beer out of zillas. I have no need for my CO2 tank and regulator now. The benefit of being inline is I can push beer out of second zilla. With a gas jumper cable and a spunding valve a third port for beer out is needed. The only downside is my perlick faucet will leak below 9 psi so I will either need to hook up my co2 tank inline via gauge port, or use my picnic tap when the psi drops that low.