30 psi seems way to high to keep the beer at. It's fine if you are trying to quickly carbonate it (withing a couple days), but you will want to back it off or you will over carbonate it. 12 psi at 40 degrees gets me the right volumes of co2 for most of my ales. I set it to 12 and it is ready in about 10 days, no need to adjust for serving.