EcoONE Monthly is the safe, non toxic core of the ecoOne system that naturally solves most spa water treatment problems and dramatically reduces spa maintenance. Added monthly, it effectively stabilizes pH/alkalinity, eliminates scum lines, foam, itching and rashes and helps to alleviate dry skin by reducing the overall chemical use. EcoOne Monthly decreases drastically the demand on your sanitizer (chlorine/bromine), while increasing the overall enjoyment of owning your spa.