I know it’s not a necessarily “chlorine free” option, but does anyone know about using chlorine dioxide as a primary method in sanitization? It’s a much safer option than traditional chlorine, as it doesn’t create undesirable residuals as a result of the chemical reactions that take place. Many water treatment facilities use this all across the world as their disinfection protocol, and it’s even approved (although purposely demoted) for proper water disinfection by regulating authorities. It’s even simple enough to be able to make at home for the average DIY’er, so long as proper safety measures and procedures are implemented.