I don't care what kind of TP we use as long as it's soft! The easiest way to clean the tank is to fill it with some water and drive around and then dump. About sensors, your "instinct" is your best sensor. Get a "gauge" on how much your tank holds and then make sure you dump on a schedule when camping. I quit using electronic sensors years ago. Common sense drives a better solution. (I dump every day when camping. If on full hooks up, I'll add water. If not full hook-up, I'll backflush the gray water tank into the black water tank and dump the black again into my tote. But when leaving or driving to the next destination, put 4 or 5 gallons of water in the tank to slosh around real good.)