Hi
I have used the Up atomiser on a number of my tanks, i haven't really cleaned one yet, and i have no loss in performance to make me want to yet. (been running at least 10 months now)
Just a couple of quick thoughts:
You say it blowing the pipe off?
The core is a ceramic pipe, through which the CO2 flows, i find it strange that this can become completely blocked are you sure you don't have a block elsewhere?
Have you checked your connecting point on the up atomiser is not blocked?
Have you checked that your CO2 hose has not gone brittle and is just slipping/popping off? Trying replacing the hose, also may be worth trying it without the non return valve, just to eliminate them.
Have you accidentally increased your working pressure (ideally should be 1.7bar ish?)
Good luck
Andy