The GEO method is a home-made cleaning technique that’s been around in the RV community since (at least) the early 80’s. Where the name came from no-body seems to know, but the original method is HERE. The original formula uses chlorine, but that can ruin your valves so these days most RVers use a slightly modified method with just 2 common items, both of which you can get at any big department store:
- Calgon Water Softener -> This stuff helps to break down water surface tension, clean scum and prevent hard mineral deposits. I’ve used Borax on occasion when I can’t find Calgon and find it works just as well.
- Dawn Dishwasher Detergent -> The “original formula” blue detergent is excellent at cutting grime. Laundry detergent works too.
After you dump pour 1 cup of Calgon and 1 cup detergent into the tanks. Leave them in until your next dump.