I have the Snake River Ultra 8 Tank Monitor on my C387 #96 and finally after a few years of messing with it finally figured it all out. Originally, the installer wired the blue and red wires backwards on all tanks. (Got that figured out year one and fixed.) Even then the waste tank monitor did not function. That became this year’s project.
What I discovered was this. The holding tank has two strips painted down the side that are supposed to eliminate the need for the foil strips that are used on the other tanks. Onto this was attached the copper foil patches wired to the sensor which was wired to the control head. At least on my holding tank, there was no electrical connection between the copper patches and the conductive strips on the tank. The symptom of this was that the reading was always empty until the