[MpG]

As near as I can see, each time the fluid stops moving, it looks like the fluid level in the reservoir has dropped down to the height of the divider. Still think it's worth trying what I suggested earlier - run the pump, refill the reservoir (with the pump still running), seal the reservoir air-tight, and then cycle the pump off and on a few times.

Another option is to lay the case down on its side, twisting the reservoir so it's still upright, of course. It might simply be that long tube length going upwards that's causing the problems.