[[File:Redsand.jpg|500px|thumb|Iron-enhanced sand filter media adjacent to a wet pond (Minnesota Stormwater Manual)<ref>Minnesota Stormwater Manual. https://stormwater.pca.state.mn.us/index.php/Design_criteria_for_iron_enhanced_sand_filter</ref>.]] | [[File:Redsand.jpg|500px|thumb|Iron-enhanced sand filter media adjacent to a wet pond (Minnesota Stormwater Manual)<ref>Minnesota Stormwater Manual. https://stormwater.pca.state.mn.us/index.php/Design_criteria_for_iron_enhanced_sand_filter</ref>.]] |