New Slingshot this spring and have camped 3 times. I dump the black water first then the grey water. The 2nd time, I had a sewer line at my site and was able to really flush both tanks. When I went to dump the black water this week, I got a small residual when I removed the cap to install the hose. This would suggest a small amount was getting by the closed valve. Anybody have experience with this or suggestion on what the problem may be?
As an aside...I also used a clear elbow with hose flushing this last time and got both tanks flushed to a clear water level.