Quick take
Do not replace iron media on a generic calendar. Track iron breakthrough, backwash performance and the manufacturer’s media-life guidance for the exact system.
What controls lifespan
Iron concentration, manganese, hydrogen sulfide, pH and daily water volume all change loading.
Backwashing matters
Regenerating media beds depend on adequate backwash flow to remove accumulated precipitate and prevent channeling.
Oxidation stage matters
Air injection, chlorine, peroxide or other oxidation methods can change how much work the media performs.
Test treated water
Rising iron or manganese after the system is a stronger replacement signal than age alone.