Filter system capable of reducing iron, manganese, and hydrogen sulfide using manganese greensand filter media. Manganese greensand is formulated from a glauconite coated with varying types of manganese oxides. Soluble iron, manganese, and hydrogen sulfide are then oxidized and precipitated by contact with these oxides. Precipitates are then filtered and removed by the backwash step. Oxidative capacity of the media must be restored through either periodic regeneration with a weak potassium permanganate (KMnO4) solution or a continuous chemical feed of KMnO4, chlorine, or a combination of both.