I buy 2 gallons of the pink stuff and I usually have about a half gallon left over from the previous year.
I drain the three tanks, fresh, grey and black water.
I bypass the water heater, drain and siphon the remaining water out. Then replace the cap. I drain the plumbing by the low point drains, and then close them.
Next I blow out the lines with about 40 psi, and follow that with the pink stuff being careful to fill the traps and leaving some in the toilet bowl. Don't forget the outside shower.
After letting the pressure bleed off I press the freshwater intake to allow some pink stuff to come out the connector.
Almost forgot, I add the stuff, I forget its name, to the gas tank and run the engine and genny so it circulates thru the engines. Still have to do this step.
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