Welcome to TFP! The most common disadvantage is pool staining. Unlike iron or organic stains, it can be quite difficult to remove. There is also the potential for swimmers to experience hair color changes and fingernail discoloration too. See the link below for more info.
Welcome to TFP! For a wealth of pool care information please check out our free Pool School. If you are in need of specific help then we encourage you to Register and ask us here in the forum!