We will be away from the RV for 2 to 3 weeks starting next week. Our tanks are about half full. My instinct is to go dump them prior to leaving, put water and happy camper in. Husband likes to dump them when full and wants to wait till after we return. Which is correct?
If it was me I would empty all the tanks. At least the grey tanks that way it won’t smell. Your black tank has happy camper which will continue to break down solids. Either way you won’t hurt anything in either tanks. Like I said if it was me I would empty them all.