For weather decks, like mine I first cleaned the deck using an Oxygenated
Bleach. I have photos before and after using an oygenated bleach. In the photos yow will notice how the oxygenated bleach cleaned up the stains and mold. This should you how well ogenated bleach works.
You can see the photos and articles at http://decks.hemmingsjones.com/photos.html