Let's face it. No matter how clean you get the black water tank, the next person to sit on the toilet gets it dirty again. My approach is to dump it when it needs it. Make sure that there is alway enough liquid in the tank to allow it to slosh around. Always make sure there is bio active deodorant in the tank. When we get home from a trip, I flush as thoroughly as I can with a hose down the toilet. I try to never let it be totally dry unless winterizing.
Not the only way, but has worked for a long time for me with several RVs.
Ken
__________________
|