We opened up the access to the top of our offending holding tank. I spent a half hour taping everything up with plastic just in case there might be some leakage. Then jack unclamped the hose and tried to pull it off the barb. And tried. And tried. Then I tried. And tried. We could twist It and turn it but we couldn’t get it off even one ridge of the fitting. After about an hour we gave up, reclamped it and went back below to snake the hose from the other end. Yep, it’s still clogged. Ugh.