Upon having everything filled and ready to go with the carbon filter I had bought before the old tank bit the dust, I fired it up and black water was filling the tank...... Note to self, (Always, run water through a new carbon filter well, before initial use). Now that is out of the way, the first thing I noticed is how quiet the unit is! What a welcome nicety.
I've not heard of using a carbon filter with ultrasonic cleaning. Typically it is used for odor and taste in, eg, an RO system.