Thx PoolDoc,
I starting sanding the pool today and it is working every well but slow. I can see a noticeable change in color and even my wife likes it. It is a very slow process. I tried a regular disc sander with 180 grit sandpaper so I would not gouge the walls and it did not work very well. It have been all hand sanding. I am using a medium course foam block I got at the local hardware store. If anyone else has some advise, I would love to hear it.
Thx