Swimming pool concern is a term that refers to the potential presence of ALGAE in a swimming pool. ALGAE is a type of plant-like organism that can grow in water and can cause a variety of problems, such as discoloration, unpleasant odors, and clogged filters. ALGAE can also be dangerous if it is ingested, as it can contain toxins that can cause illness. Therefore, it is important to take steps to prevent and control ALGAE growth in swimming pools.