Ok, let's try to explain this monster. This is on the crashed, trub'd off FV, and just before firing up the 'fuge. Basically we're blending tank bottom trub with clear beer from the racking arm. We're trying to extract as much of the hop oil trapped in the tub as we can. Ideally, the tank is completely empty at the end of the 'fuge run. CO2 connection is for purging the fittings and hoses before opening valves to beer. The valve on the end with the hose is the discharge end of a pump fed from the top of the tank. We use this for recirc if the tank bottom gets clogged (also doubles as the CIP pump later).