Rid-X

When I had a septic system my septic guys (friends of the family), told me to add Rid-x now and then since it helps liquify stuff better....seemed to work for me since I only had the tank cleaned out twice in 25 years..... and the only difference in a septic tank or a black tank is one is cement and one is plastic, one empties over time and one empties when you pull the handle. I do use a little Rid-x when I know my rig is gonna sit for a month or two, also make sure there is water in the tank during that time...