I have been buying it by the bottle but would like to know why you need a magnet in case down the road I need to buy at the pump.![]()
Just a wild guess, but looks like maybe the DEF fill tube diameter is the same as the main fuel tank, and sometimes the uninformed try to fill the DEF tank with diesel fuel - guess the magnet bit is used to decease the DEF filler diameter so no tries to get a standard diesel nozzle in the DEF filler...
The reason for buying at truck stops is 1 it is fresh they go thru a lot of it and 2 it is about half the cost. if you don't tow it is no big deal . If you do it can be a big money saver, since you go thru at least double when towing heavy.