[DutchmenSport]

About black tanks? It seems for some folks they work and for others they don't. Mine have always worked in 3 different travel trailers and now my Montana High Country. What do I do that might be different from everyone else?

When breaking camp, my black tank is dumped, and I always backflush the grey shower water into the black tank. With a somewhat full grey tank, I can easily backflush 3 times, each time sucking out more TP and "stuff". You need a 3rd valve, like a Flush King to close off the end and allow the grey to flush backwards into the black tank. So, first, is getting as much 'stuff' out of the black tank as possible.

Second, after dumping and backflushing the black tank, add about 5 gallons of water back to the tank and go to your next destination. The sloshing inside the tank will pulverize the sides of the tank and beat water against the sensors, thus removing any debris that stuck around.

Do this every time you break camp, and your tank sensors should work (unless there is a broken wire, or the actual sensor itself has gone bad... which is very unlikely).

Driving with TP and "stuff" in the tanks will also slosh around, but any "stuff" in the tanks will catch on the sensors. You've gained nothing. So dump first, backflush to get the extra TP out, add some clean water, and then drive! Easy to do, costs nothing after your purchase the Flush King, and works!