Waterline Stains
 

I have a 1971 20' SF and have always taken water stains off over the winter with Oxalic Acid and then following that up with a cleaner wax. The waterline typically comes back after a few uses and then I do the same thing over the next winter. This year I removed the water stain and used Ultima Paint Prep Pro (compound) and then followed that up with Ultima Paint Plus Pro (sealant) and hoped that would inhibit or reduce staining. I've only used the boat twice since I have applied these products and the waterline stain has already returned; however it is faint. Does anyone know of a way to prevent waterline stains? I'm assuming the Oxalic Acid may have opened up the pores in the paint and possibly made the issue worse.

thanks,

water line stain
 

Try on/off do not let it stay on there long put it on wipe it off right away