I have algae on the walls, decorations, and live plants. I've already tried wiping off the algae, but it wouldn't come off. I have the light on for 7 hours a day. I do regular water changes. I have a snail and some fish that like to pick at the algae. I have a 20 gallon so I can't get any big algae eaters. I still have algae after all the common recommendations given.