My sensors operate somewhat erratically, figure they must have some female hormones!!
Haven't tried it, but have read where Calgon does a good job using procedure as mentioned above using dishwasher soap. Only reason I haven't tried it is that I use Oxy Kem 2 in the black tank and don't want to input anything foreign which might harm the action of the Oxy Kem.
I use a Sewer Solution when dumping and this allows for slower discharge of the tank and I think probably the tank flusher does a better job as a result of the movement of fluids in the tank.
On gray water tank, I occasionally use some of the TST Orange Power in it when it gets about half full and then let it fill up further before dumping. That seems to help a lot. This also helps to hold down the sour odor which you can get from the gray water tank.