Sheila,
Those sensors never seem to work after a while. I mostly figure mine based on days and usage. Kind of have a running count in my head of how many times someone has used the toilet.
The sensor in our last 5th wheel never worked (we bought it used), so I got in this habit. The sensor in Sunshine is still working. Hopefully will for a while. When we were at a CG with no sewer hookup, I always used the #1 TP in the waste basket, #2 TP in the toilet system. Of course emptied the waste basket every morning. I imagine I will get Mom using this system too. It seems the safest not to overload the black tank with paper, even broken down leaves shreds. I do use the Cottenelle wipes, but they go right into the waste basket.
I bit the bullet and bought a Thetford hauling buddy (not sure of the name, but you know what I mean). I got mine on Amazon. It was less than CW, but they were still really proud of it. Did get free shipping, so that helped. If we are staying at a state park for a couple weeks, I sure don't want to have to break camp to go dump if I can avoid it. Paul is going to carry it on the carrier he has for the back of his MH for his scooter. I told him he had better make sure it is strapped on really well, cause it was too expensive to lose going down the road.