True North - if you do a search of the forum, you'll see that this subject comes up here about once a month. Put aside an afternoon and read the threads. They all say the same thing, the Geo Method and ignore the sensors.
Those with OCD who simply cannot ignore the sensors spend a lot of what is supposed to be leisure time worrying about what is a simple function. The black tank will fill up in a predictable time frame and react the same each time is gets full. When the time comes and the "I'm full" event occurs, dump it. It's that simple.
I do the Geo Method once a year, just before I put the MH down for the winter. I can dump at the storage facility so I put 10 gallons of water and a cap each of Calgon and Dawn blue dishwashing liquid in the tank at home. The 2 mile trip to the storage yard sloshes this around and I dump and then wand the black tank. I don't care what the indicators say (1/2 tank BTW) because I know the tank is empty.
