If you want a more permanent cure, and you do remove all your LR, a short freshwater dip of each rock will explode the algae cells as well ~ I've never seen anything on best length of time to dip for, but it does work. Be sure a pick the rock over well before dipping to remove any inverts, and I don't think I would dip anything that has coral on it, but if you don't have a lot of coral, it may help.