I recently cleaned a composite deck using a chorine cleaner & all the coloring came off deck only on areas that were horizontal not verticle or were a floor matt sat & was kept protected from weather. Now the home owner wants me to build him a new deck. I have cleaned trex deck and have not had a problem at all. This deck is a weather best composite deck. I have a feeling that the weather best product puts a light color coating on the outside of the board and the trex decking is color through the entire piece inside and out. Does any one know anything about this problem.