I am looking for a better way of ridding myself of Coraline algae that has formed on the glass. I currently use an old credit card to scrape it off, but I think the movement is disturbing the tank so much. I have hear a razor blade is better, but I would prefer a natural way of doing it if possible. I also have a ton of rocks and corals that are close to the glass where my hand can't reach down and scrape it very well. Any suggestions.