Oscar just a quick thought and apologies if you did but did you connect the green wire to the case to simulate the on button? I forgot to mention it earlier.
The sediment I've always noticed has been crud basically, but one other thing I did find was a small pump located in the top giving a very gentle circular motion seemed to help a little.
Here's a pic of mine after a couple of pieces have been done so waiting to be cleaned and showing the pump:
