grey tank

Get one of those scrubbing bubble characters you see on TV and dump them in the tank. Let them out when they are done. :) Remember what you're putting in those tanks. As the scum dries on the sensors they can't give you an accurate reading. The gauges are put in as a "feel good" item when you're looking at purchasing a coach. No one makes a gauge that is accurate for very long, if at all....Dennis