I have seen them but never have used them. I just fill the tanks drain when full, flush with the black tank flush system. I fill the black tank 2-3 times with fresh water and empty completely. Then fill the tank with about 5 gallons of water and Aqua-Chem. With the 2 of us it takes about 4-5 days to fill the black tank (we use lots of water flushing the toilet.) we also keep the grey tanks closed. With the washer and shower going it only takes about 2 days to fill the grey tank and use the grey water to flush out the hose. The reason we keep the all the tanks closed is because it is the number one way that cockroaches and rodents can enter the unit
2013 Redwood 36RL. 2005 Dodge 3500 DRW 4X4. 6 speed manual transmission. South Bend dual disc clutch.