lanerd wrote:
How do you know the tank is NOT empty? If you are sure that there is still something in there you might want to get one of THESE. You can get one at Walmart...not the same brand, but will do the same job. Hook up a garden hose to it and back flush into the tank.
However, if you are going by the monitor...you might just be empty as those things are pretty much worthless for accuracy.
Ron
This is what it took for me when I couldn't drain my black tank. I use it occasionally now just to keep things flushed out.