After reading through many of the posts here, I see I am not alone with this problem.
My husband installed a brand new deck made from TREX decking material. After about a year we started seeing mold spots on the decking. Now, about 18 months later, these mold spots are darker and constant through out the whole decking floor. Not on the rails or posts.
Please Trex or someone - come up with a product to make these Mold Spots go away! Stand behind your product like many of us thought you would.