CYA, stabilizer, and conditioner when above 50 ppm will begin to change the the color of your plaster investment if it is a colored finish. Look what it did to this fitting. The CYA in this pool was over 200 ppm. The CYA weakened the pigment in the fitting and the UVA light from the sun finished off the discoloration.
G&B Tile and Plaster 960 North Mill Street Lewisville, Texas 75057 Phone (972) 906-0142 www.poolsub.com