Algae is by far the most common problem for pond owners. Often times pond owners try to rake or pull the algae from their ponds only to have it come back in a few days. Algae controls come in both liquid and granular form. Liquid products should be used when the algae is floating on the surface or in shallow water (up to 3' or 4' deep). Granular products should be used in deeper water and for bottom growing algae and chara.