Willy1

We are new hottub owners just purchased a used Hot Springs SX. The underside of our hottub cover turned a big reddish brown stain that will not come off after we overfilled the tub and it foamed up. Have tried vinegar, bleach and serious scrubbing. Are there any products to remove the stain? Not sure if it’s rust or tannin from well water. We use Baqua brand products and do not have a water softener. Thanks for suggestions.