BIO-DEX CHXO5 5 lb Container Chlor-Ex Sanitizer. Chlor-Ex can remove extra chlorine in pools and spas. Although chlorine is an effective sanitizer, it can be harmful at high levels. Over-chlorinating is an easy mistake to make. You should test your water regularly to ensure that it doesn't have too much chlorine, which can be a problem. It will irritate swimmers and bathers. Chlorine can also have a detrimental effect on the filtration system in the spa or pool. It can also make the liner begin to deteriorate. Chlor-Ex removes the excess chlorine from spas and pools before it can damage the equipment and irritate swimmers' skin and eyes. It's easy to use and dissolves quickly in the water. The product leaves your water properly balanced and pleasant for swimmers.