Recently I kegged for the first time and everything seemed fine. I primed the keg, let it sit for a couple weeks, hooked it up in my kegerator, waited a couple days, and then pulled off the first glass. It came out perfectly carbonated and kept doing so for a couple weeks. Then, for some reason, the carbonation appeared to change as all I get now is foam. I have a 7 foot line on the beer side. I changed the delivery pressure from 13psi to 10psi to help minimize the pressure drop, but that didn't work. I do have a tower, but if I needed a tower cooler, the beer should have been all foam the whole time instead of changing after two weeks. Is there something I'm missing here? Should I just bleed off the pressure and bring it back to 10psi, hoping that works? Thanks.