I've heard about using the blue tote for dumping so you don't have to move the rig. When the tote is not as large as the tanks you are dumping from do you just have to wing it and hope you shut it do...
The tote will come with a fitting to attach a short (approx.) small garden style hose (included). This allows you to fill the tote with grey water and not overfill it. I never use the tank for black water. Just to smelly and potentially messy. No thanks!