The best way to mange moss & algae growth on your roof is to prevent it from growing in the first place.
You can save thousands of dollars over the lifespan of your roof simply by applying an annual moss treatment powder to prevent moss from taking root on your roof. My annual moss treatment program costs only $75, and includes the application of up to 4 pounds of zinc sulfate powder which will keep your roof clear of moss and lichen for the season.
With our long and wet winters there is simply no permanent solution to prevent moss growth on your roof, short of trimming trees to give the roof as much sunlight as possible. Zinc strips along the roofline, while great in more forgiving climates, simply are not effective enough in our PNW. Annual treatment is required to keep your roof moss free.