How much mixture for Geo Method of black tank cleaning

[Timmer]

Hi all,

We just had a toilet clog due to kids not flushing enough water down after use. We got it unclogged but our sensors are still reading full. I have read here and elsewhere about the Geo Method and am going to give it a try. I'm finding quite a few variations to ratios in the recipe. Most call for creating a mixture in a pale or jug that is around 1 cup Calgon, 1 cup Dawn, and 1 gallon of water. From what I've gathered I believe there is a difference between doing this after every use and doing it for a major cleaning. What I'm not seeing for the major cleaning situation is use x gallons of mix for every x gallons your tank holds. Is one gallon of this mix enough to clean the tank or should I be adding several gallons of the stuff based on tank size? One gallon wouldn't seem enough to slosh around and clean things, but maybe I'm wrong? I'm also worried about adding too much as I imagine there would be a lot of suds.