I've been using that Sta-Bil stuff forever and have never had a problem with it and E fuel stored for over a year...
I use it in all my 5 and 2.5 gallon gas cans that I keep for the lawn equipment, home generator, etc.. (I keep 2- 5 gallon and 3- 2.5 gallon cans for storage at home)
I use this for the entire year. After a year, if I haven't already used it, I'll just put in one of my vehicles and refresh with new gas and Sta-Bil.
I do try to run it out of the gas tanks it's in, but once I left it too long in the Honda gen (probably over 2 years) and had to drain it out, but once I put fresh gas in, the gen ran fine.
Anyway, your aux tank sound fine if you can rig it up safely...
Even at a 1/4 tank, that's probably around 25 gallons of gas in the rv's tank...
Good luck!
Mitch
