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How Does a Chemical-Free FOB Iron and Sulphur Filter Work?

How Does a Chemical-Free FOB Iron and Sulphur Filter Work?

Tired of cleaning awful rusty stains off toilets, grout, fixtures, and tubs at your home, cottage, or cabin? The FOB Iron and Sulphur Filter is a chemical-free solution that will save you time, money, and improve the quality of your water for you and your family. Read on to learn more. 



FOB air over media systems are totally chemical-free and don’t have any filter cartridges to change. They use air to oxidize the iron and a low amount of sulphur from your water before it enters your home.


A FOB Iron and Sulphur Filter system draws air in through its air intake, by way of an advanced electronic control valve to form an air cap within the top of the media tank.

In everyday use, water is sprayed through the air cap to begin oxidizing the iron and sulphur out of the water. The media traps any oxidized iron and holds it in place while the water flows into and up the riser tube to the whole house or cottage. Every three days the air over media filter automatically reverses the flow and backwashes all of the Birm media flushing the iron, dirt, and sediment from the media and into the drain. Then the air cap is rebuilt sucking water through the injector before the filter is put back into service to continue to oxidize and remove sulphur from your water.

What you're left with is fresh, clean water... and NO RUSTY STAINS! 


The FOB system works at removing up to 4 ppm of iron and a low 1 ppm of sulphur with a ph at least 6.8.

If you've got higher amounts of iron and sulphur in your water, you'd be better equipped with a FOK system, which you can learn about in my next YouTube video here.  

Unsure what's in your water? Wondering what water treatment solution will work best for your home, cottage or cabin? We offer FREE Analysis of your water test results and make a recommendation based on your concerns and the chemical analysis of your water. 

Take advantage of our free water test evaluation by clicking here


As you can see, Iron and Sulphur Removal systems are easy to use and maintain as there are no filters to change or chemicals added to your water. This method is the easiest and most inexpensive way to significantly reduce iron content from your family's household water.

At Water Estore, we offer easy do-it-yourself installation, selection and Iron and Sulphur water filter advice with our YouTube videos and on our blog. Check them out!



To continue to learn more about the maintenance, winterization and installation of these chemical-free iron and sulphur systems and check out the different types available, go to my next video here and I’ll see you there!

Video Transcript

Gary The Water Guy:
If you're getting iron staining at your home, cottage or cabin, you're looking for a solution. I mean, you're tired of cleaning up those toilets with those rusty stains, the staining in your grout, all around your fixtures. There's got to be a fix for it. You've heard of an FOB. What's FOB even mean? Does it work? Is it chemical-free? Well, I'm going to explain it to you. I'm going to explain it to you right now.

Gary The Water Guy:
Yeah. I am Gary The Water Guy and I simplify water filtration to help you conquer crappy water for your family. So an FOB is an iron filter. It's a totally chemical-free type system. There's no filter cartridges to change. It just totally works off air. How can it possibly do that? Well, air is used to oxidize the iron out of your water. You can see that process taking place in your home right now. You'll probably notice that once you flush the toilet, you clean the toilet. It's nice and the water comes in. There's no color to it. There's no rust stains. It's fine. Then you go away for a couple of days or a week, if it's a cottage or a cabin, and you come back and you see it's all rusty inside. How did that happen?

Gary The Water Guy:
Well, what's happened is the air is oxidizing the iron out of the water. So what we want to do, you want to oxidize the iron out of the water, but inside this tank and get rid of that iron before it enters your home, cottage or cabin. So how does it do that? Well, basically how it works is this, is inside this tank, the top, oh, I don't know, top third of this tank or so is an air bubble, a giant air bubble. Whenever you run your water, your water spray through that air bubble and what that does, it oxidizes or brings out the iron, just like in your toilet, brings it out out of solution, out of the water, and then the water passes down through the tank.

Gary The Water Guy:
But the bottom third of the tank is a media and that media is called berm. That's actually what the B part of the FOB means. It stands for berm. So what it does, it attracts that oxidized iron in the water and it attaches to it. So then the water keeps on going down, but now the iron's been pulled out of the water. As the water gets down to the bottom of the tank, it enters into this filter here or the screen. So it's installed this way. So you can see the waters passes down through the media and then goes inside the filter here and then goes up through the middle and then it goes onto your whole house.

Gary The Water Guy:
So after three days of the water running through that cycle, whenever you're on your water, it accumulates inside the tank. Well, obviously we have to get rid of it. So after three days, it has to backwash to remove that. How it works is it reverses the flow. So now water comes in here and it goes down through this tube, gets down to the screen, comes out through the screen, goes up the tank and it actually expands the media. It lifts the media off the bottom of the tank and expands the media to the whole size of the tank. So it actually pushes out that air bubble out through the top, pushes it out through the drain. So as it back washing all that media and flushes all the debris to the drain.

Gary The Water Guy:
About 15 minutes or so it takes for it to do that and then it starts sucking in air. So it actually sucks in air through here. So it's a little difficult to see on the unit, but this is what it looks like. It's a one way valve with a screen on it. So sucks the air in through here and recreates that air bubble. How it creates that suction is through this air injector, this little Venturi. You'll hear when it's going through its cycle, its air draw cycle, or it'll say on here brine cycle, but it's an air draw cycle, you can hear gurgling coming from here, but you can also hear water running very slowly. That's what's creating that suction to bring the air in through here. So it rebuilds that air bubble, and then it puts it back into service.

Gary The Water Guy:
So normally it does that in the middle of the night. We want it to do that at some time when there's very little or no water usage in the house. Like I say, it takes about 45 minutes for it to go through that whole cycle. Once it's gone through that cycle, it's all set to go for another three days.

Gary The Water Guy:
So one question you might have is will an FOB also remove sulfur from your water if you have both iron and sulfur? It will, but it's only really set up for a very small amount of sulfur removal. I mean, this'll do four parts per million of iron removal. No problem. If you've got a little bit of sulfur, you get a little bit of smell, occasionally it'll do that too. If you've got higher amounts of sulfur in addition to the higher amounts of iron in your water, then you're probably going to be better suited to an FOK instead of an FOB. Also, you need to watch the pH. So the pH has to be a 6.8 or higher for this system to work properly. So for some more information about air over media iron and sulfur filters, in other words, how to install, how to maintain, how to winterize, just go over here to my next video and I'll see you there.