Horst probes
I have installed the new horst probes in my black tank easy job and haven't verified their accuracy yet..if you do it plan on replacing the electric ends on the wires cause they are different.
Forum Discussion
I had the Horst probes installed when I bought my coach in 2011. I can't tell you exactly how accurate they are because I can't see into my tanks, but I can tell you that when I dump they read empty or nearly so and I've never had any backing up or flooding because of a probe reading. I use no chemicals, I use no special toilet paper. I use a lot of water. Generally I dump when my black tank is about 1/2 full & the grey is at 3/4. I don't do any special rinsing of anything.
