I'm trying to clean the walls of my pool as green algae is starting to form, especially around the big light in the deep end. However, I'm having a hard time actually cleaning it. I'm not sure if I'm not getting enough leverage or what, but when I brush, the algae doesn't really seem to be coming off very well. So I thought I'd get a handheld brush and then just get in the pool and scrub it. Is this a good idea? If so, any particular type of brush to get or not get?