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As you'll be working with bleach to remove algae from your roof, sidewalk, or other areas of your home, safety is important. Put on thick, protective gloves, as well as a pair of safety goggles. These will keep you safe from bleach as you work. If there are any plants near where you're removing algae, you should protect them as well. Cover plants in a plastic tarp to keep them safe. You can buy algae cleaner online or at a local department store. It should be mixed with bleach and water in a cleaning pump to remove algae from your home. Mix a quart of bleach, a gallon of water, and 1/4 cup (60 milliliters) of a heavy duty algae cleaner in your cleaning pump. If you don't have a cleaning pump, you can buy one online, borrow one from a friend, or rent one at a local hardware store. For small algae spots, you can simply place the solution in a spray bottle. Spray the area where you see the algae thoroughly. You want to cover the infected area completely with your solution. Once the area is sprayed down, set a timer for 15 minutes to let the solution soak in. You do not need to scrub the solution. It will break down the algae on its own. Take a hose and use this to rinse off the solution. Make sure to rinse the solution off completely, especially if you're cleaning algae from somewhere off your roof. Leftover residue from your cleaner can cause damage. Once hose water runs clear, the algae should be gone.
Put on gloves and goggles. Mix bleach, algae cleaner, and water in a pump. Spray down the infected area. Rinse the area with a hose.