hey guys i purchased 3 tons of pellets that just wont burn correctly.they start off fine but after 2 hours or so the burn pot starts filling up with pellets and ash.any ideas I tried a bag of white lightning and they burn perfect.Im only burning them on setting 2 or 3 so I dont know why they would be doing this.and not after 2 hours?the bags do not have a name on them. any ideas?????I cant adjust air flow it is all manually controlled. thanks