One secret to controlling odors and extending the life of your RV holding tanks is to add plenty of water to the black water holding tank after you empty it.
How much water should be added?
You want the bottom of the tank to be completely covered by water and depending on the size of the tank this might require 3 toilet bowls of water or it might take 7 or 8 to completely cover the bottom of the tank.
What else should we keep in mind?
Add plenty of water to the bowl every time you flush it so there is enough water in the tank at all times to assist in controlling odors.
Happy RV Learning!