Just racked first batch of brew to keg. I am running CO2 in at 30 psi since noon today (plan is for a few days). I have checked it a couple times today and have noticed that the pressure has dropped slightly (a few psi each time). Is this normal when force carbing or is there a leak. I got a new regulator and tank with a used corny keg. The keg looks in good shape but anything is possible. It is my first time hooking up the co2 so its also possible im just keg stupid, but I thought it might be normal to lose a few psi's while pressurizing a keg.