We had a 2016 Adventurer 80RB. To keep weight down they fitted a very meager 6 gallon grey tank which as you can imagine doesn't take long to fill even when being mindful of the limitations. However, this wasn't the actual issue. From the time the camper was new I would empty the tank from full and the monitor panel always said 1/3 full when it was empty (not a drop coming out). I kept thinking how could the sensors be gummed up so soon ? This was a grey tank after all, and the unit was brand new. Eventually I discovered that the tank was installed incorrectly. The tank was installed at an angle that kept the tank from emptying completely.
Some things never change!!...Adventurer camper manufacturers were originally Slumber Queeen campers built in Aldergrove, BC....I bought a new Slumber Queen in 1988 and had same issues with grey tank. Took it back to factory and found that tank had been installed upside down!!...tank at that time was manufactured with tank top flat, and bottom sloping to the rear for drainage...good tank, bad install....they never took it out, just shimmed the dump valves downward. Fix never was any good, and later dump valve seal started to leak...arrrgggg!!
