The short answer
Air injection oxidizes iron and sulfur with an air pocket and no chemicals; media filters rely on the media's chemistry and have pH and oxygen limits.
Side by side
| Air injection | Media (Birm, greensand, KDF) | |
|---|---|---|
| Chemicals | None | Some media need regenerant (greensand) |
| Sulfur | Handles moderate levels | Depends on media |
| Limits | Maker's iron and sulfur limits | pH and oxygen limits (Birm: pH 6.8+ for iron) |
Penn State's guidance
Greensand suits combined iron and manganese of about 3 to 10 mg/L; above 10 mg/L, oxidation then filtration works best; Birm needs dissolved oxygen and pH of at least 6.8 for iron.
Filters we cover
Air injection: iSpring WCFM400K Air-Injection Iron Filter, AFWFilters AIG15-25SXT-34 Air Injection Gold Fleck 2510SXT Air-Injection Iron Filter. Media: iSpring WGB32BM Iron Filter, iSpring WCFM550K Iron Filter.
Products mentioned
Air-injection iron filter · iSpring
iSpring WCFM400K Air-Injection Iron Filter
Air-injection iron filter · 12 GPM
Air-injection iron filter · AFWFilters
AFWFilters AIG15-25SXT-34 Air Injection Gold Fleck 2510SXT Air-Injection Iron Filter
Air-injection iron filter · 12 GPM
Media iron filter · iSpring
iSpring WGB32BM Iron Filter
Media iron filter · 15 GPM
Questions readers ask
Which iron filter is best for well water?
It depends on iron, manganese, sulfur and pH; test first and match the filter's limits.
Do air injection filters remove sulfur smell?
They're sold for iron and hydrogen sulfide within the maker's stated limits.