I have a 14' X 6' Tamco Evergrain composite deck and railing in Maryland. It's the cedar color which is no longer available. The deck was installed in 2005. It gets green with mold and then turns black, I believe from the nearby airport? I originally heard about Corte Clean on a radio do it yourself talk show which promoted it as being the best product and available at Lowe's, where I initially purchased the product. They unfortunately no longer carried it, so I skipped a year, because it was more expensive online. I only used the power washer that year. Corte Clean is a fantastic product that additionally gets rid of the citronella candle, food and other stains without taking off a layer of the composite like the power washer. I've been using it for years.