The trick to having accurate sensors is to keep the black tank "clean". Here, "clean" is a relative term. What I mean is to keep the tank free of toilet paper and feces after dumping. The best way to do this is when you get ready to break camp and travel, empty the tank the best you can.....then add about five gallons of water plus a cup of liquid laundry detergent (I use Oxy-Clean....some use Dawn dish washing soap). Travel to you next destination and once there empty the tank once again and add a couple or three more gallons of water back into the tank prior to using the toilet. You may have to do this several times before you really get the tank "clean", but it will definitely work and your sensors will read accurately.
As mentioned, a tank rinse device really helps and a clear connector will keep you informed of not only what is coming out of the tank but also when it is empty. Also, in spite of many people posting about putting ice in the tank....it's been proven that this is a fallacy and does nothing constructive. Another fallacy is the very common use of tank chemicals. If you have an odor inside the rv, you have a problem with a seal, gasket or vent and needs to be repaired. Chemicals are like a band-aid...temporary fix. Use plenty of plain ol water prior to using the toilet, during the use of the toilet, and when dumping the tank.
Good luck and I hope this helps.
Ron
