Unwanted algae are a problem in most freshwater aquariums. Algae appear in many forms: tufts of short beard algae, long strands of hair algae or mats of fine blanket algae. Not only is algae unsightly - covering aquarium glass, gravel and ornaments - it also clogs filter intakes and causes problems with water chemistry. Algae growth is promoted by phosphates from food, fish wastes and strong light. To manage aquarium water better to avoid algae issues, Blue Planet recommends limiting light to 8hours per day; also consider external sunlight hitting the aquarium. Partial water changes of 20%, or 10L changed for every 50L of aquarium water, every 2 weeks, will help ensure your aquarium water remains healthy and algae free. Most important is the type and amount of food given to fish, always remove leftover food, and where possible feed a quality diet to your fish.