Probably crap on the sensor. The best way to know where your at, is to remember when you dumped it. My gages have very seldom gone to empty in the two years since I bought the unit. Grease, soap, poop, anything on the sensor will throw off the reading.
I use the sound and sight method to know when to dump. The galley sick will make a bubbling sound just before it's full. The shower will stop draining when the grey water tank is full and the toilet will have a airlock bubble when you flush it before it stops working because the black water is up to the vent pipe. This method works real good and the monitor gages will read full just before the tanks get full. Technology is not all it's cracked up to be.
Yeph
Linear Mode
