Air-injection iron filter · iSpring

iSpring WCFM400K Air-Injection Iron Filter

Air-injection iron filter

Updated October 2026

Quick verdict

A sensible air-injection iron filter for well water with iron or sulfur.

Strength
Air-injection iron filter.
Trade-off
Check pH and iron limits.
Right buyer
Well water with iron or sulfur.
Service flow (maker)
12 GPM
Media
Air Injection
Material
Fiberglass, Manganese Dioxide, Plastic
Dimensions (seller)
16.4"L x 14"W x 66.8"H
Product weight
104 lb
Warranty
1-year warranty
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What it does for your water

The iSpring WCFM400K Air-Injection Iron Filter is an air-injection iron filter using Air Injection. Its listing gives a flow of 12 GPM.

An air pocket in the top of the tank does the oxidizing here: iron and sulfur drop out on the media and leave with each backwash, so there is nothing to refill.

Match its limits to a water test: iron, manganese, pH and sulfur. It belongs ahead of a softener so iron never reaches the resin.

The listing also gives features listed Air Injection and Advanced Catalytic Media; mounting Point-of-entry; media Air Injection; power Water Pressure Powered; capacity stated as 400000 gallons; model WCFM400K.

The listing gives dimensions of 16.4 in (L) x 14 in (W) x 66.8 in (H), a shipping weight of 104 lb and wcfm400k, drain tube, power supply, user manual in the box.

Warranty, per the listing: 1-year warranty.

Is it the right unit for your house?

Choose it when

  • Well water with iron or sulfur
  • Protecting a softener from iron

Pass on it when

  • City water without iron

Where it wins and where it loses

Wins

  • Air-injection iron filter
  • Air Injection
  • 12 GPM flow

Loses

  • Check pH and iron limits
  • Needs a drain for backwash

Limits to know about

  • Figures are the maker's or seller's own; check fit and capacity against your water test and your equipment's manual.

Maker's figures

Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.

Model numberWCFM400KRetailer
Features (seller)Air Injection and Advanced Catalytic MediaRetailer
Dimensions (seller)16.4"L x 14"W x 66.8"HRetailer
MaterialFiberglass, Manganese Dioxide, PlasticRetailer
Mounting / installationPoint-of-entryRetailer
MethodOxidation Reduction PotentialRetailer
Service flow (maker)12 GPMRetailer
Product weight104 lbRetailer
Model nameWCFM400KRetailer
Warranty1-year warrantyRetailer
MediaAir InjectionRetailer

Units to weigh against it

Other iron and sulfur filters in the catalog

Every iron and sulfur filters on one grid · All iSpring units we cover

Final verdict

A sensible air-injection iron filter for well water with iron or sulfur.

Where to buy

Our links open this exact model's product page. Prices and stock change; check what's included before you order.

Prices change often; the button shows today's price.

Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure

Questions buyers ask

What is the iSpring WCFM400K Air-Injection Iron Filter for?
The iSpring WCFM400K Air-Injection Iron Filter is an air-injection iron filter using Air Injection. Its listing gives a flow of 12 GPM.