Checking thru posts, I see this black ring at water level is referred to as a "scum line"
Is there a natural product (like baking soda is used in BBB and that is readily available in supermarket or hardware stores) that can be used to remove it without upsetting chem balance?
Is there a natural product (like baking soda is used in BBB and that is readily available in supermarket or hardware stores) that can be used to remove it without upsetting chem balance?