We live in the woods and have 2 large front and back decks. Our decks which are grey in color not only get dirty, but we have to deal with a lot of ugly mold. Until 2015, both decks were composite T&G TimberTech Floorizon decking and the only thing that killed mold was a bleach and water mixture used often. In 2015, we replaced our back deck’s composite T&G TimberTech Floorizon decking with capped composite Trex Transcend grooved porch decking. To our dismay, bleach could NOT be used on capped composite Trex Transcend grooved porch decking. Corte-Clean was recommended. So, we tried Corte-Clean in 2015 and have used nothing else since on both our decks. Not only does it easily clean our decks and kill the mold, the decks only need to be cleaned a few times a year and stay clean much longer. The product continues to work every time it rains if you don’t wash all the product off after it is clean. It will continue to clean any time it receives moisture until it is thoroughly rinsed. We won’t use anything else on our decks and just wish we had known about it sooner.