I have a 5 gallon keg from a local microwbrew in the kegerator currently. It is a pale ale. I also have the traditional blower set up for my tower. Since the keg was introduced, I have had great luck with no foaming issues but now that I am toward the bottom of the keg, foam is all I am getting. My pressure is set around 10 psi and has been since I introduced the keg. The last few beers have been all foam though. Any thoughts? Is it because of all the head space in the keg since there is little beer left. Any ideas would be appreciated.