First buy a filter
The first suggestion is to purchase a $18.00 filter at Wall Mart in the RV car section.Flush your tank and re-fill with filtered water. Then add a cup of Bleach. Now for those who swear that this will eat the aluminum tank, it will- but not in our lifetime, if you are not heavy-handed with the bleach. We are looking to kill any organic matter in the water, not bleach your clothes. If you can aquire clorine dioxide, omit the bleach.Ian