Ultraviolet irradiation is a good way to purify water in the pool if it is often performed quite often. Otherwise, ultraviolet will not be able to fully ensure the purity of water in the pool for a long time. The essence of this technique is that ultraviolet radiation penetrates into cell DNA and deprives them of the ability to multiply. To ensure ideally clean water in the pool, it is recommended to use chlorination after ultraviolet irradiation.