first time rv - Itasca Navion

If you are not dry camping and are connected to a sewer hook up, then lots and lots of water in the black tank, including left over soapy water from washing the dishes. When I get ready to dump the tanks, I run water into the black tank until the gauge says full. In my Via, the bathroom sink drains into the black tank and that is probably the same with your NAVION. Once the tanks are empty, I put two capfuls of Calgon down the black tank, and 1 ounce of the TST Orange RV Tank Treatment. I used the same method with my previous rvs and have never had a problem with odor from the black tank.