Brushing your pool regularly to prevent algae growth is the single most important preventative maintenance task you can do. Do NOT confuse brushing with vacuuming just because your vacuum head has brushes on it. Brushing should be performed at least once a week with a separate brush attached to your telescopic vacuuming pole. Be sure to brush every square inch of your pool. Your chemicals can not do their job and kill algae if they can’t “get to it”.
To elaborate a bit, picture a piece of tape placed on a wall. Spray the wall with water and then peel the tape off. The wall is dry behind where the tape was, right? Think about algae in your pool the same way. If it begins to grow on the walls or floor of your pool, chemicals may only begin to kill the surface as it continues to grow. Brushing removes it from the surface and puts it into suspension allowing it to be killed completely. Your pool filtration system can then remove it from the water. Just because you might not visibly see algae, doesn’t mean it is not there. So remember, brush, brush, brush.