One thing that helped was squeezing the ballooning portion, not allowing it to ballon as the pressure increased. Making it a two hand job, one on the top, holding the adapter, the other the pressure point. In my previous attempts i noticed that there was an air gap in the top of the clear plastic tube that never really got filled with water. When i squeezed the ballooning portion, it went away. Will test in a bit to see how it filters now. I've preprimed this thing like 10 times. Hope it still works.
I achieve a good flow rate when im prepriming but not in gravity mode. Its flowing but its not as fast.