Iron Filter Maintenance: What You Actually Need to Do

An air injection iron filter asks very little of you. It backwashes itself, there is no yearly service, and every 6 to 8 years the media inside it (the Katalox Light granules that catch the iron) is replaced. What is left for you is short: check the clock after a power outage or a trip, know which signs are normal and which are not, and plan the media change when the time comes. Here is all of it, for the filters we sell and the valve on yours.

Caller "This is a rental house, so I don't want something that requires a lot of maintenance."

Aidan "No, there's no annual maintenance. Every 6 to 8 years, you clean the tank out and re-bed it with new media, and that's all you have to do."

A caller asked me that in June 2026 while choosing a filter for a rental house. This page is the long version of my answer.

What maintenance does an iron filter actually need?

Almost none, and most of it happens on its own. The filter backwashes itself, and every 6 to 8 years the Katalox Light media is replaced. Everything in between is a quick check when something changes.

This page is about air injection filters with Katalox Light, the kind we sell. If you own a Hellenbrand Iron Curtain, start with its maker's manual; the two are compared in Iron Curtain vs Katalox Light.

Which valve is on your filter

The buttons depend on which valve you have, so look at yours before you press anything. Filters bought before mid-September 2026 have the older Fleck 2510 SXT, a black rectangular head with a small display. Since October 1, 2026, every size ships with the Fleck 2510 AiQ, the new version of the Fleck 2510, with a round face and a large screen; in between, it depends on the size, and the head tells you which one you have. It is the valve in my maintenance video below.

How often your iron filter backwashes

Ours ship set to backwash every day, and you can set it to run less often. During the backwash the flow of water is reversed: the water goes down the center tube, comes up through the Vortech plate, moves the media in a circular motion to clean the bed, and carries the iron out to the drain. Then the valve draws in fresh air to rebuild the air pocket at the top of the tank. I explain the air pocket in how an iron filter works.

If your house uses little water and you want it to backwash less, go to every 2 days, and to every 3 days if the water stays clear. Pentair's manual for the older valve says not to set it longer than 3 days. If iron starts bleeding through, go back a day. Change only the backwash days and nothing else, and on the AiQ text me before you change a setting. On the older valve, the screen switches between the time and the number of days until the next backwash, which is how you know it is counting.

Every iron filter has to backwash. The only systems we sell that do not backwash are our carbon tanks and our non-backwashing acid neutralizers.

How much water the backwash uses

For a healthy septic system in good working condition, the answer is yes, it is safe. The backwash is water and the iron it flushed out, with no chemicals in it. How much water depends on the size:

The drain line, the air gap and what the backwash looks like at the drain are in why an iron filter backwashes.

How to clean an iron filter

Cleaning an iron filter means running an extra backwash; nothing gets taken apart and nothing gets poured in. Run 2 or 3 after the media is replaced to clear the dust, or one any time you want to flush it.

Do not add bleach, vinegar or an iron cleaner to try to bring old media back. One caller ran a bleach treatment and 3 backwashes on 6-year-old media, and the rotten egg smell was back right away. At 6 years, that is when it needs to be replaced.

Pentair writes its manuals as service guides for trained technicians, and their list is longer than mine. The part it names is the injector, the small nozzle that pulls air into the tank, with its screen. Pentair's manual for the older valve says to replace the injector, air check, piston, seals and spacers every 6 to 12 months as needed, and the AiQ manual adds a yearly inspection. If the filter no longer draws air, Pentair's troubleshooting lists a kinked drain line, water pressure under 20 psi, a blocked drain flow control, and a plugged injector or screen. Text me before anyone takes the valve apart.

Leaving for vacation

When we go on vacation, even if it's just 3 days, I unplug the system so it doesn't backwash, and I don't come home to a flooded basement if something goes wrong. When you get home, plug it back in and look at the clock.

A power outage works the same way. Both valves keep their settings without power and keep the time for about 48 hours; after that, set the time of day again. The time flashes after the power comes back until you press a button. On the older valve, a backwash it missed runs at its next scheduled time.

Signs your iron filter needs attention

Several things that worry owners in the first weeks are normal. What matters is iron or the smell coming back after the water was clear.

For the water test, the certified well water test ($199) shows iron, manganese and pH, which is what I need to tell the media from the well.

Iron or smell coming back?

Tell Aidan how old your filter media is

Send a photo of the valve screen, how old the media is and your latest water test. Aidan will tell you whether it is a setting, the media or the well.

Text Aidan443-277-2204 Call800-460-5810Aidan

8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.

How long Katalox Light media lasts

Based on our existing customers, and 15 years of using these systems, the media is replaced every 6 to 8 years. A light-use house goes longer: with about 5 ppm of iron and 4 people, the media can last 8 to 10 years, and with 8 to 10 people it is 6 to 8. You will know it is time when iron starts bleeding through again.

Put a piece of tape on the tank with the install date, and 6 to 8 years from then, replace it. After 32 years in this business, the biggest mistake I see customers make is that they just forget to do the maintenance. What the media is and how much your filter takes are in replacing Katalox Light.

How to replace iron filter media

Only the Katalox Light is replaced; the tank and the valve stay. Our filters use Vortech tanks, so there is no gravel to replace. I recommend having a plumber do it: a loaded 2.5 tank weighs about 250 pounds, and the valve has to come off and go back on without a leak. I'm a phone call away for your plumber. If you'd rather do it yourself, text me with any questions.

1. Put the filter in bypass

   Turn the bypass handle to BY PASS so the house still has water, and unplug the valve. Pentair's manual says the system must be depressurized before service, so your plumber takes the pressure off the tank before anything comes apart.

   

2. Take the valve off the tank

   Disconnect the tank from the bypass and unscrew the valve from the top of the tank.

3. Empty out the old media

   Get the water out with a wet vac, then take the tank outside and dump the old media into a trash bag, or vacuum it out with the wet vac.

4. Rinse the tank with a hose

   Rinse the inside of the tank with a hose until the water runs clean.

5. Cover the center pipe with tape

   Put a piece of painter's tape over the top of the center tube (the pipe down the middle of the tank) so no media falls inside it.

6. Pour in the new Katalox Light

   Set the fill funnel in the tank opening and pour in all of the Katalox Light for your size.

   

7. Fill the tank slowly with water

   Take the tape off, screw the valve back on, reconnect it, and open a cold faucet. Open the main valve about a quarter of the way so the tank fills slowly and the air can get out, then open it fully.

8. Set the clock

   Plug the valve in, set the time of day, and run a manual backwash 2 or 3 times to get the dust out. On the AiQ the clock is under DATE/TIME on the Home menu.

   

Afterward, milky water and a little black dust are normal for a while; they are in the signs table above. Here is what to order for each size:

If the funnel from your install is gone, the fill funnel is $35. Another brand's tank may have a gravel bed under the media; text me a photo of its label before you order.

Add a sediment pre-filter to protect the valve

I recommend a large sediment filter before the iron filter to keep dirt and clay from building up inside the valve. It goes after the pressure tank and ahead of the iron filter: on a well, a 20 inch Big Blue with a 5 micron cartridge ($195 for the kit). The full order of a well system is in the correct order for well water treatment.

What buyers wrote after installing one

These are verified buyers of our air injection iron filter, newest first.

Frequently asked questions