HOnestly, if there is a line waiting to dump I consider it unfair and selfish to take that much time. Know a member of our camping group who does that and we all fight to be sure to "get going" before he is ready to get in line! We simply make sure the black tank is full before we empty it (adding extra water if necessary before we unhook at the campsite) and then, after dumping and closing it off, put a gallon or so of fresh water with chemicals back into the toilet. Fill a gallon jug of water before we leave campsite to do this. We've never had an odor problem doing it this way.
