I have always thrown about a 1/4th cup of bleach in the tank to keep it fresh between runs, (full tank). That's only if I know it's going to be some time between uses.
Also, we never drink or cook with the tank water, we use bottled.
Bob & Sharon
2019 Winnebago Travato K (2018 Chassis)
Past RV's: 2013 WGO ERA 70A, Chevy PW Lexor
Itasca Navion, 29' Jayco 5th Wheel