When I flush my black tank, one of the processing steps is when I have finished the flushing. I add approximately five gallons of water or until the first light on the tank level board comes on. I then fill the toilet bowl half full
(for OC half empty). I add three of the dishwasher "PODS" to the bowl along with one of the chemical bags of "AQUA KEM TOSS INS", let dissolve before
dumping toilet contents into the black tank. The dishwasher detergent pods
clean the sensors, the tank, along with liquid in the pods to make sure no
"SPOTS" are left from the hard water
. The liquid in the pods I believe
perform the same as Calgon. I have no problems with the black tank or sensors. I purchase the tub of 48 PODS at SAM'S or WAL-MART.