Hi! I filled a 5 gal. corny keg. I force carbonated for 48 hrs at about 30psi. In the keg I have a Flotit 2.0. I brought the psi down to about 12 and tried serving. Nothin' but foam! I then expelled all CO2 over time to where I could open the keg. I observed that there was no foam on the beer. I...