I have installed procell decking and I am sorry I did. I am experiencing the same condition with sunscreen as wswinford. I have used simple green, CLR, Comet, etc. and nothing seems to touch it. I chose this product because of it's "Maintance free" features. I live in Colorado Spring and after 3 months I noticed it begin to fade. Then to top off the fading, the first two boards out from the house begain to turn black like they were about to burst into flames. The Deck is on the south side of the house and it gets direct sun all day long. I am very unhappy with this product!!!