We are having a lot of friends with kids over this summer to swim in our pool. A lifeguard has been hired. She mentioned some safety equipment that is required for public pools such as a lifeguard rescue tube, spineboard, hook pole, and ring buoy. Our pool is 20x40. The rescue tube I think is a must, and she has her own whistle. We do not have a diving board or slide. I am wondering if we really need this additional safety equipment.