First I want to thank you for taking time to write that article on the Geo Method.
We just bought our first RV and it was used because we did not want to spend a lot of money on something that we may not enjoy. I am SO fussy about the things I own and take really good care of them, kinda like my care for my Harley. :-) I have spent HOURS reading things on a few forums as well as some on You Tube. I have spend the last three weeks checking EVERYTHING in the RV, frig and care, cleaning out water heater, check this and checking that. Once I have done this, then I feel better because I know for myself that is was clean and checked. :)
We are going on our first outing this coming labor day week-end and the place we are going to has sewers at each site, so tomorrow I am going to buy the stuff you suggested and put it in my tanks and it will have time to soak and the drive to the CG is approx 50 miles and will have time for water movement. The morning before leaving, I will clean the gray and black tank well before leaving since we have the dump at our site.
Thanks again for the good advise. If ever in the San Diego area, give me a shout.