When to add Sea Foam to fuel [SOLVED]

Hi Linda. That’s one of the best Sea Foam questions you can ask! You can add to fuel whether full or low. However, when adding a full can, adding to less fuel creates a greater cleaning concentration. I like to add a can or two of Sea Foam when there’s less than 1/8th a tank, then drive at least 10 to 20 miles to take advantage of the higher concentration. Can always fill up when fuel is needed. Hope this makes sense!