The issue is going to be whatever is in the tank, is going to keep flaking off. Most likely forever.
I used some stuff to seal and coat several dirt bike tanks to save them. It worked but it was a ton of work. I can’t imagine doing it to an automotive fuel tank, but I know guys do it.
Thats kind of your options...try and seal your tank, or buy a new one. Otherwise, you’ll fight this for a long time.
