I just purchased a 2012 Cyclone 4014 and I am not sure which valve is for the black tank and which is for the grey tank. I have a separate valve in the rear for the #2 grey tank. There is a door near the front marked grey #1 and black. There are two valves inside but neither one in marked. Not sure which one is the black and which one is the grey. I believe the one to the left nearest the front is the grey but I am not sure. I want to dump the black first and use the grey to flush the sewer hose. I have only dumped once so far and since there was very little in either tank it was hard to tell the color of the water as it flowed out. Anyone with a 4014 out there who can tell me which valve is which?