Unless you're draining water constantly, it is off most of the time. The water filtration system shuts off when full of 2-water and 2-salt. Otherwise you'll probably replace them once in a blue moon. If you use continuously draining machinery like the water filtration system then you will probably replace the rods every so often. Originally posted by Emurinus:The rods don't directly indicate how drained they get over time, but each rod has 90 minutes if constantly used iirc.