Abstract: For removing iron from water the present apparatus has a bed of manganese zeolite particles above an outlet screen unit and below an inlet screen unit in a container. The container has enough empty space above the treatment bed to permit substantially all of its particles to be tumbled vigorously during backwash for effective removal of the accumulated iron and other impurities trapped in the treatment bed. Each screen unit includes a pair of split rings which hold foraminous screens between them and are radially contractable for slidable insertion in the container, after which they expand radially for a tight fit inside the container. Cross bars on each split ring reinforce the screens.