Superconcentrated multifunctional algaecide for the maintenance of water in irrigation systems and reservoirs. It has a multimodal synergistic effect. It inhibits the growth of algae (both microalgae and filamentous), macrophytes, and aquatic vegetation, whether submerged or floating. It eliminates turbidity, flocculates suspended solids, clarifies the water, and gives a spectacular visual appearance to the stored water. Its various active ingredients combine different mechanisms of action, making it highly effective for the comprehensive treatment of water reservoirs.