This product worked for me.Does help to use a scotch-brite pad and lightly buff wet area..Pontoons are not white,they look new again...
If you plan on using it, the best way to apply is with a garden sprayer.
This product is a combination of acids and works the same as A/C coil cleaner, and with the same effect. It turns the aluminum white and doesn't really remove scum lines. It just covers them up. It also turns any welds black.