[ReelMagic]

When the read-out on the gauge for the waste tank seemed slow to respond or even show what was in the tank I decided to pull the sensor out (After emptying the tank) and clean the sensor. At that time I calibrated the sensor to see if the readout was accurate. Found the sensor didn't go to the bottom of the tank and that results in the gauge reading zero (empty) till the tank gets approx. 1/4 full. Then the gauge starts reading and is somewhat accurate..... I empty the waste tank every weekend so it generally doesn't show anything on the gauge since the tank is less than 1/4 full..... Also, there is a valve in the engine compartment that forces fresh water into the waste tank on top of the sensor to ensure its clean and not blocked. I use that valve when ever I think the sensor isn't working.... My experience.