What do most people do with their back wall and sides of their tank? I have been working to get coraline algea to cover the sides and back. It was looking good until I had hair algea cover everything in the tank. As I have been fighting that, and I am making progress, the back wall is sorta brwon and pink. I scape the back wall each night but it never really looks purple and pink now. So I am thinking I should use a razor blade (glass tank) and clean everything down.