Also, might want to invest in a clear sewer fitting to attach to your outlet/hose.
The idea, when dumping, you can see what's headed down the tube... And can see when the tank has stopped draining.
If you have a tank flushing system it is also handy to be able to see when you are getting clear(er) water out of the drain.
In my area you can pick up this clear fitting for about $5, was well worth it. Not that it's exactly exciting to watch poo headed downhill, but, it's good to be able to see that the tank is empty at least.