Regarding cleaning the black tank, i used a clear 45 degree clear elbow so I can see what is passing and when the tanks are empty. I use the onboard black tank flushing value during the black tank dump. Once it runs clear I use a Camco Swivel Stik Sewer Holding Tank wand. I hooks to the water hose and you insert it through the inside toilet hole. I found it will clean the sensors and the black tank extremely well. All of the above black tank ideas and experiences are dead-on.