No I think the tank is fine. In fact when I first had this problem I peeked in the tank with a small mirror and a bright flashlight at night. Holding the light aganist the tank really illuminated the inside nicely. The tank looked clean as a whistle. I had more stuff floating around my lawn mower can than what was in my almost 20 yr old boat. What I just learned recently is don't mix old fuel with the new ethanol, it causes some kind of sludge/ shelac. Run the boat out of the old fuel and then replace just what you think you'll need with the new stuff. When this started I'd ask around if anybody else was having a problem, nobody seemed concerned. That has changed in this last month, the conversation is all about fuel. By the way in between the last post and this one I found that product and have introduced it to the fuel system. I'll keep my fingers crossed.