Originally Posted by TROONORTH
I am somewhat concerned about what may be causing your 'burping'. Is this some new way of emptying the tank?
The "inlet" pipes hang down into the tank a bit, trapping air at the very top of it. Burping caused by that trapped air escaping through an inlet pipe as liquid level rises within the tank, filling the area formerly occupied by the trapped air.
From a practical standpoint, if the tank has burped once or twice, it's time to stop using it. Further usage is very likely going to lead to a mess.