[scottandanna]

I have the gray and black valve pulls in the "control panel" area in the storage bin, but a second gray tank valve pull back under my TV/fireplace slideout. So I am sure I have two gray tanks, and I am sure the sink runs into the one with the valve under the TV.

I have heard of bathroom sinks going into the black tank, maybe even showers, but never the kitchen sink. That is actually kind of a gross idea. Considering that when I finally filled my sink tank to the point where the sink would back up, glad that was NOT black tank liquid!!!