If you have mold/algae on the side of your house, you can hire ia professional and have your house power washed. Many in the community have used Shooters Softwash or CBUS Power Washing
If you want to do it yourself, there is a recommended product called Mold Armor that you can find at any local home improvement store or Amazon. You can spray it on, wait for about 15-20 minutes and spray it off.
Mold Armor Demo