Controls growth of algae in swimming pools. Prevents algae growth throughout the winter season. For use in all pools treated with biguanide, chlorine, bromine, salt water or minerals. It is compatible with most chemicals used in pool water and will not damage tile, concrete, metal, or plastics. Do not premix with any foreign material, such as soap or other chemicals before application. This product works best when added by itself directly to pool water with the pump running. Wait 15 minutes before entry of swimmers. Pools with heavy growth of algae should be cleaned prior to using this product. Keeps pool water clear of visible algae and unsightly deposits. It improves filter operation and reduces the need for other chemicals.