We have been RV'ing for about 30+ years.? We don't use the blue stuff or commercial brands of sewer treatments.? We use distilled white vinegar and rid-x.? The vinegar is a natural degreaser, biodegradeable, and will lubricate the rubber gaskets on your valves.? The rid-x or other enzyme product will supply the bacteria to break down waste and turn your sewage to liquid.?
The vinegar will clean the monitor probes for your tank monitor.? My monitor panels have never had a? problem, with the exception of the current one, which came from the factory with a bad wiring connector.? Once corrected, we've had no problems.
We pour about a cup of vinegar down the commode, after we dump, add a cup of rid-x and about a gallon or so of water.? When we set up, we also put a splash of vinegar down each of the bathroom sinks and kitchen sinks to keep the traps clean.
We don't have odor, we haven't had problems with valves, and our monitor panels continue to work.? I buy the cheapest distilled white vinegar I can find.?
Remember that the holding tanks are septic tanks.