I have a composite deck in Wisconsin which I purchased from Menards. It gets mold, especially in the shade. It use to take me 6 hours of power washing to get it clean. It now takes me 10 minutes with Corte Clean. I love that you can see it working when it hits the stains, as it foams up and turns dirty. This is my 3rd year using Corte Clean. While this product is not cheap, it is definitely worth the money. I have recommended it to my brother, whom also purchased a composite deck from Menards. I will say, the first time I used it, I wasn't that impressed, until several days later, after the morning dew, the deck then looked amazing! I will be using Corte Clean spring/fall and just ordered more today. Keep up the good work Corte Clean!