I use
Purogene sanitizer with citric acid for
once-a-season sanitizing. After that, since I usually refill with filtered, unchlorinated well water, I add a small amount of Purogene (1 oz per 30gal water) with every tank refill to keep the water clean (the water may sit in the tank for weeks between uses).
I rinse and drain the tank once after sanitizing and it doesn't leave any strong chlorine taste/smell behind, but I don't normally drink out of the freshwater tank.
It's the same
chemical airlines use for sanitizing airplane water tanks.
