I agree with the last few posts too
Just draining the black tank does not clean the black tank. I flush thoroughly until the water runs clear. If I'm not going to be using the camper for a few days I'll add about 1/2 gallon of bleach and dilute that with 5 to 10 gallons of clean water. This keeps the tank from generating odor while sitting in hot weather.
I flushed my black tank this past week and filled my 45 gallon tote 4 times. Needless to say our seasonal CG doesn't have full hookups. But at least I know it's clean now. I also close the black dump valve during the back flush process to allow water to accumulate in the tank. You will be amazed at how much sludge comes out when doing that. I'll use the blue stuff with the the next 3 or 4 tank dumps and then flush again. Lots of work in this CG but no smell when dumping or flushing the toilet. YMMV!
Nick, Sharon and Finnigan