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How Does a Chemical-Free FOC Sulphur Filter Work?

How Does a Chemical-Free FOC Sulphur Filter Work?

Do you have that horrible rotten egg smell in your water? That nasty smell is sulphur and you'll notice it when the sulphur in your water comes out of your faucet and hits the air. 

There are different types of water treatment systems that can help to remove sulphur from your water using chemicals and chemical-free options. Today we're going to talk about chemical-free units.


These FOC Sulphur and Iron Removal systems are totally chemical-free and they don’t have any filter cartridges to change either. They use air to oxidize the sulphur from your water!

Here's how the chemical-free water treatment process works:

  • FOC systems draw air through its air intake in its 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 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 media flushing the iron, dirt and sediment from the media and into the drain.
  • Then the air cap is rebuilt by sucking water through the injector before the filter is put back into service to continue to oxidize and remove sulphur from your water.
  • This whole process usually takes about 45 minutes to complete. 

The FOC Sulphur and Iron Removal system works fine at removing up to 1 ppm of iron and 4 ppm of sulphur with a ph at least 6.5. There are no filters to change or chemicals added to your water, so it's super low maintenance. 

A fully automatic FOC system is perfect if you want to solve your sulphur/iron problem with the least amount of on-going expense. It features a power cell backup to retain settings and time during power interruptions. And choosing a chemical-free system like this is much friendlier on your septic system, too!


Need help determining the best water treatment solutions for you and your family? Give Water Store Midland a call today at 705-527-5900 or book your free in-home water analysis online via the link below. 



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:
Do you have that horrible rotten egg smell in your water? You know that sulfur? It's just terrible. I mean, you get used to it to some degree, but your guests come over, and they remind you of the smell. It's so embarrassing. You've heard that there's different systems that will get rid of that smell. There's chemical systems and chemical-free systems like this FOC, but how can that possibly work? Well, I'm going to explain it to you right now.

Gary The Water Guy:
Hi, I'm Gary, The Water Guy, and I simplify water filtration to help you conquer crappy water for your family. This is a chemical-free HUM FOC iron-sulfur filter. Basically, how it works it uses air to oxidize out the sulfur out of the water. If there's a little bit of iron, less than one part per million of iron, it'll also oxidize that out. But again, it's totally chemical-free, and there's no filters to the cartridges to change. Nothing like that. It's super low maintenance.

Gary The Water Guy:
But let me explain to you how it works. It works off air, oxidizing out the sulfur out of the water. When your water comes out of the faucet, it hits the air, and that's where it gives off that sulfur smell. Before it hit the air, that smell wasn't given off. So what we want to do is go in to introduce the water to oxygen inside this tank to get rid of the smell inside the tank. So, inside this tank, it has a big air cap, a big air bubble, if you like, at the top of the tank. Whenever you run your water, your water is sprayed through that air bubble, and it brings out the sulfur smell inside the tank. Then as the water passes down through over the media, and the media inside here is catalytic carbon, or a charged carbon, also called centaur carbon, and that's actually what the C in FOC stands for.

Gary The Water Guy:
But as that oxidized sulfur and iron passes over that charged carbon inside the tank, it sticks to it. Then as it gets to the bottom of the tank, it comes in contact with this screen or this filter at the bottom, if you like. So the water flows down through the sides of the tank, flows into this filter, and then it flows up through the middle and then goes on to your whole house. So on an ongoing basis, whenever you run your water, it goes through that cycle. After three days of use, we have to clean up that media inside there and get rid of any of the iron that's been filtered out. So at a predetermined time that the unit is set for, usually 2:00 AM, 3:00 AM, some time like that when there's no water usage in the home, it goes through its cycle.

Gary The Water Guy:
There's actually two aspects to the cycle. The first one is that it backwashes. Now what it does is it reverses the flow. Now the water goes down through this tube, comes out through the screen at the bottom, and forces the media up. In fact, it expands the media from filling just about a third of the tank to actually filling the whole tank. At the same time, it's pushing out that air bubble, and it backwashes all that oxidized and precipitated iron out to the drain. Once it's finished doing that, then it sucks in air through this air injector at the top.

Gary The Water Guy:
This is what it looks like. It's a little easier to see when I hold it up here. But it's a one-way valve, so it sucks air in through here. And how it does that, there's this little injector. I'll put it this way here. This little injector that sits inside here, and what that does, it creates the suction. It's a Venturi effect. It creates the suction and sucks in air. So it rebuilds that air bubble. Once it's rebuilt that air bubble, it puts it back into service. It takes about 45 minutes for it to go through this whole cycle.

Gary The Water Guy:
This HUM Water Care sulfur filter, as I said, also removes iron. How much? It will remove about four parts per million of sulfur, but only up to one part per million of iron. So if your sulfur content is relatively high, but your iron content is relatively low, this is the best choice for you. To learn more about these chemical-free air over media, iron-sulfur filters, how to install them, how to maintain them, et cetera, just click up here. That'll take you right to my next video on this series, and I'll see you there.