[canesfan]

Don't know for sure on yours, but I can share this if it helps. Mine has 2 gray tanks and I knew that from the literature and crawling around looking under it to confirm. What I couldn't figure out was how to dump the second gray tank. I could see the pvc running from the rear up to the main drain outlet, but there was only a black and 1 gray handle there. I finally started tracing the pvc back to the tank and where I never would have noticed it there is a valve handle stuck up in the wheel well above the rear tire. You have to be a contortionist to reach it. They put things in strange places on this stuff so dig around and you might find your second valve.