In your post, you say it's "sitting at 8 psi" now. That's not enough. Turn it back up to 12 psi, and keep it there! If you're turning it down to serve, either remember to turn it right back up, or get longer lines so you don't keep turning it down to serve and blow out the co2 all of the time.
Broken Leg Brewery
Giving beer a leg to stand on since 2006