I just installed the See Level sensors on our 2002 fifth wheel. We camp for about 3 months of the year where we do not have sewer hook up but we do have water and electric. The OE readout has never worked (we bought this unit 6 years old). Our toilet drain has a dog leg so you can not see down into the tank so by the time you see water you are full or plugged. My wife is always asking how much room do you think I have, am I going to run out of water while your fishing, is it safe to do dishes???
Not anymore..I think it is going to eliminate a lot of uncertainty.
I will say that because our tanks are around 8"tall and you have to cut the sensor strips to fit tank, that the percent readings we get jump in 6% intervals, not 1% as I would like but that is 16 different levels of full rather than 1/3rds.