In the process of replacing my liner in my 18” AGP...and wondered if I have the right idea on removing a few spots of rust on the pool walls. A couple of the spots are just surface rust but a couple spots (About 2-3” in diameter and 2-3” in height) have some bubbling on the rust although it has not permeated through the wall..would the best course of action be to use fine sandpaper or a wire brush designed for rust (I’m not worried about the surface rust spots, just the spots the have the bubbling)? Also, after the rust has been removed, I was going to use some ZRC galvanizing spray to spray over the spots but do I need anything more after the spray for added protection? Thanks in advance!