Unwanted growth on your roof can spread before you know it. Whether it’s moss, mildew or fungus growing up there, you should do your best to get rid of it as soon as you notice it because it will only continue to spread if left unchecked. Bleach solutions are safe for non-asphalt roofing and easy to use. You should use a non-bleach solution if you have asphalt roofing.
Its great that you don't use a lot of technical wording that can confuse the clients. Highly professional and to the point.