At the FMCA rally in Farmington, one of the seminars covered this topic and the presenter suggested using peroxyde vice bleach. Odorless, tasteless, and one ounce per gallon will sanitize your tank. I usually add a 12 oz bottle, approximately 12 gal of FW before driving home from my last stop. Finally got rid of that chlorine smell and taste. Be aware also that chlorine bleach attacks some types of seals.