Do you have a black tank rinse device? If yes, then on you next day to travel, empty both tanks and with the rinse device, put about 5 gallons of new water into the tank (use sink faucets for gray tank) and then put into each tank 1 cup of liquid laundry detergent (and with the Calgon if so desired) and travel to your next destination. The sloshing of the soapy water in the tank will act as an agitator and remove all debris from the sensors. Once at your destination, empty both tanks and put more clean water back in and use the system as you normally would. Repeat this procedure every time you travel and I assure you that your tanks/sensors will function as designed.
Ron