I have a 2016 - 3100. Have owned this unit about 3 years. When I dump the tanks everything goes fine. When done there is still liquid in the drain hose. I even took to the factory to have repaired, said they added a fitting that should correct the problem, it did not other than relive my pocket of a lot of dollars. The only way I can drain the hose is to put a bucket under the 3" sewer hose connection and drain about a gallon and half of liquid out of it, then the maserator pump dischsrge line will drain. I leave my tank valves open during this process so to get air in. Factory could not fix it, has anyone else had this problem and what did you do to correct it?