If you’re interested in whole home water filtration solutions, you’ve probably come across KDF filters. These filters are becoming increasingly popular because of their effectiveness in reducing a number of common water contaminants, including chlorine, heavy metals, and microorganisms. They’re used as a primary treatment, pretreatment or combined with other purification technologies for effective impurity removal.
In this guide, I’ll be providing an in-depth look into KDF filter media – what they are, how they work, their advantages and disadvantages, and more.
Table of Contents
What Exactly Are KDF Filter Media?
KDF is short for kinetic degradation fluxion. This type of media consists of granules made from high-purity copper-zinc, which are designed to produce a redox reaction – either reduction or oxidation – to greatly reduce common water impurities. In the KDF redox process, which is certified by NSF international, impurities are changed into harmless substances that can be effectively removed by backwashing. Electrons are transferred between molecules and new elements are created as a result.
The KDF redox process produces a chemical reaction that is most commonly used to target contaminants such as heavy metals, chlorine and hydrogen sulfide.
KDF technology, which was produced more than 30 years ago in the United States, is certified by NSF Standard 61, which ensures it won’t leach any toxins into water, and also meets standards put in place by the EPA and FDA for copper and zinc drinking water content.
KDF filter media systems contain no chemical additives, making them safe to be used in whole-home filter systems to effectively treat drinking water. They can also be designed for industrial and commercial use.
Granule Variations of KDF Media
There are four common forms of KDF combination copper/zinc media: KDF-55, KDF-85, KDF-F Fine Mesh and KDF-C Coarse Mesh. Each granule variation of KDF is slightly different in water treatment performance and what it reduces or removes.
KDF-55 granules are designed to electrochemically reduce and remove soluble heavy metals and chlorine in the water . Heavy metals in water can be changed into harmless substances by KDF-55. You’ll likely find a KDF-55 filter in a whole-home application, a dedicated faucet filter, or a showerhead filter.
KDF-85 granules are effective at filtering out iron & hydrogen sulfide. Bacteria can also be effectively removed, making this type of filter media ideal for treating well water and preventing a buildup of harmful microorganisms. You can usually add a KDF-85 filter to a whole-home system or a water softener for extra efficiency, as it controls scale. It can also be used as a standalone filter.
KDF-F Fine Mesh
KDF-F fine mesh is typically combined with other filtration media, such as an activated carbon filter, to improve the overall performance of filtration and extend filter lifespan. You may find KDF-F filter granules in whole-home and dedicated filter applications.
KDF-C Coarse Mesh
Finally, KDF-C coarse mesh granules are another option for removing chlorine and water-soluble heavy metals. Like KDF-55, these filter media may be used in showerhead filters, faucet filters or whole-home systems.
How Does KDF Filter Media Work?
With KDF filter media technologies, water flows through a cartridge or tank before it passes out of your faucet or showerhead. Whether you’re using whole-home KDF filter media or dedicated shower or faucet filter systems, water will have to pass through the redox media at some point before it can leave your pipes.
KDF filter media uses a combination of copper and zinc, which produces an electrochemical reaction/ redox reaction when water flows through. In this reaction, electrons in the filter media swap places with the contaminants in the water. The KDF media then alters these contaminants so that they’re no longer harmful. This transference of electrons is known as a redox reaction.
What Contaminants Are Removed By a KDF Water Filter?
The contaminants removed by KDF media depend on the type of media you opt for. Some types of KDF media can remove lead, chlorine and hard water minerals, while others can remove iron and hydrogen sulfide, lead, mercury, nickel, calcium and magnesium, and microorganisms like bacteria, algae, and fungi.
Some of the contaminants removed by KDF process media are aesthetic, such as chlorine and chloramines. Others are more harmful to health, and taste or smell-altering, such as hydrogen sulfide, which gives water a rotten egg odor, and lead, which gives water an unpleasant metallic taste. Some contaminants, such as bacteria, can pose health problems when consumed and may cause diseases like E. Coli.
If you incorporate KDF-F filter media with an activated carbon filter, or you installed a sediment filter before a KDF filter, you would benefit from an even broader contaminant removal. What makes this type of filter particularly unique is that it won’t be damaged by hot water, so it can be used to filter water in a showerhead too.
Let’s look at how KDF media can reduce or remove particular contaminants from water:
- To remove chlorine, a KDF 55 media is typically used. In this KDF 55 water filtration process, free chlorine is converted into chloride ions, harmless components that are water-soluble. Two negatively charged electrons are required to convert free chlorine into chloride.
- To remove iron, a KDF 85 media is required. This type of KDF process media can remove up to 99% of water soluble iron by converting ferrous iron cations into ferric hydroxide, which is insoluble and can be removed from the filter media with backwashing. In this case, the chemical reaction used is known as oxidation. You may see this type of water treatment used alongside filters such as activated carbon block filters and polypropylene, which can improve the effectiveness of filtration, typically at your home’s point of entry. KDF also controls hardness scale.
- To remove hydrogen sulfide gas, KD5 85 media is used to convert hydrogen sulfide gas into insoluble sulfide. Sulfide is harmless and will be removed from the KDF process media when the system backwashes. It’s the copper in this type of KDF process media that transfers an electron to the sulfur gas, producing water and copper sulfide. This type of KDF media, being so effective at removing hydrogen sulfide, is particularly useful for treating well water.
- To remove heavy metals such as copper, nickel, chromium, lead, & mercury, you can use KDF 85, KDF 55 or KDF-C media. Any of these water treatment options removes up to 98% of these contaminants. When water passes through the KDF 55 (or similar) media, it converts soluble metal cations into insoluble atoms, using the process of reduction (redox).
- To inhibit the growth of, and control, microorganisms such as fungi, bacteria and algae, KDF media rapidly produces hydroxyl and hydrogen peroxide, which allows for direct electrochemical contact between the media and the contaminants. KDF media can be used alongside activated carbon block and granular activated carbon water filtration to extend the lifespan of these filters. It may also be used for the same purpose in reverse osmosis filters or ion exchange water softeners.
Where Are KDF Water Filter Media Used?
You can use KDF process media either as standalone applications or alongside a whole home water filtration system. If you have city water, using the right type of KDF media will reduce chlorine and chloramines, which are added to water during disinfection, and lead, a common contaminant that often leaches into water through pipes. Other heavy metals may also be removed by KDF 55, KDF 85 or KDF C media.
If you have a private well, you can use KDF process media to remove common well water contaminants including iron and hydrogen sulfide. Electrons are transferred between molecules to produce harmless substances in place of the impurities. By treating your well water before it reaches your home, you can not only ensure it’ll taste better (especially being free of the hydrogen sulfide rotten egg odor), but it’ll also be safe to drink thanks to the media’s ability to inhibit pathogen growth.
KDF process media can also be used for industrial, medicinal and commercial uses. In water treatment systems that are used in restaurants, hotels, food processing factories, and laboratories, this media offers an effective, reliable water filtration solution.
Advantages of Using a KDF Filter
There are a number of benefits of KDF process media that make them the more appealing option compared to other water filters, like carbon filters.
Some of the biggest benefits of KDF media include:
Can be used with hot water
Common filters such as activated carbon filters can’t be used with hot water. The heat could damage the structure of the filter surface and prevent it from being able to work effectively to trap contaminants. KDF process media, on the other hand, is safe to use with hot water, making it an ideal solution in showerhead filters, where water will most likely be hot.
Can inhibit bacteria growth
It’s hard to find a water filter solution that’s capable of inhibiting the growth of bacteria, fungi and algae, as most filters don’t have a small enough pore size to trap contaminants so tiny. Because this media uses a chemical process to treat water, rather than a filter cartridge, it’s an effective water treatment for bacteria, and reduces or removes other harmful microorganisms like algae.
Can support other water filters
Even the best water filters usually have their limits. A KDF filter can be used in conjunction with other filters, such as granular activated carbon (GAC) and activated carbon block filters, to offer a broader contaminant removal and extend their lifespan. If you want to remove chlorine and heavy metals as well as bacteria and iron, for example, you could use KDF process media alongside a carbon filter for the best results.
Not too costly
KDF process media are relatively affordable to buy when compared to other filter types. One of the big benefits of KDF media is that they require minimal maintenance, with no regular filter cartridge changes required, so you won’t need to budget for looking after the media as you would with others. With hot water backwashing you can reuse the media and extend the life or replace on average once per year. Always check the manufacturer’s recommendation for the guide.
There are four different types of KDF process media, and each uses a slightly different process to reduce or remove different types of harmful contaminants, from heavy metals like lead, mercury and others, to chlorine and bacteria and algae, chromium and other dissolved solids. This type of filtration can produce a redox reaction or oxygen reduction (redox) for sulfur and iron removal, two contaminants that many filers struggle with. Granular activated carbon filters and similar water filter treatments can’t be amended for different uses as KDF process media can.
The majority of KDF process media contain harmless components that are completely recyclable and contain no chemical additives. Because they’re recyclable, when your filters are no longer effectively filtering your water, KDF can simply be recycled and replaced with no negative contribution to the environment.
Disadvantages of KDF Process Media
While the positives outweigh the negatives, it’s worth being aware that filter media KDF does have its setbacks:
Not ideal for organic chemicals
Organic chemicals such as VOCs, pesticides and herbicides, organic cysts, nitrates, fluoride, viruses, arsenic, pharmaceuticals and other substances aren’t best handled by KDF filters. You’ll need to use KDF filter in conjunction with water filters that can remove these contaminants if your water supply contains them.
Requires regular backwashing
Though you won’t need to spend lots of money on maintaining process media KDF, you will have to put in the work of backwashing the media with hot water. KDF, as we know, converts harmful contaminants into harmless components such as water soluble lead, water soluble chloride, and other water soluble cations. When the filter media KDF is full of these harmless components, it needs to be backwashed to evict the contaminants. If you’d rather not do this, you can simply exchange the kinetic degradation fluxion media with a new one every 9 to 12 months.
No EPA registration is required
The EPA has reviewed KDF purification technologies and concluded that they require no EPA registration. This can be considered a bonus in terms of safety, unless you’d rather have the security of an EPA registered filter just in case.
Frequently Asked Questions
Which is best, activated carbon filters/ KDF water media?
It depends on what you’re personally looking for. In terms of contaminant removal, the oxidation/ reduction and other KDF processes make it effective in removing a whole host of contaminants, including iron, hydrogen sulfide, heavy metals like copper, lead, mercury and others, bacteria, algae, chromium and other dissolved contaminants. KDF is better at removing inorganic contaminants, while activated carbon targets organic harmful contaminants. Activated carbon filters & KDF filters use different processes to remove contaminants, too; KDF uses the chemical process of oxidation/reduction (redox) to convert harmful contaminants into harmless electrons, while activated carbon uses adsorption. Using a combination of carbon filters & KDF media together, rather than using either as a pretreatment or primary treatment, will typically have the best results and extend the lifespan of both filters.
When it comes to lifespan, with whole-home granular activated carbon (GAC) or carbon block filters, every 6 to 12 months, you’ll need to buy new filters. KDF systems, on the other hand, can last for 6 years with regular backwashing.
In simple terms, what is a KDF water filter and how does it work?
Kinetic degradation fluxion media are used to produce a chemical process – oxidation/reduction, to convert contaminants into harmless water soluble substances. Examples of these substances would be water soluble lead & dissolved metals such as copper, and water soluble chloride, converted from lead, copper and chlorine found in most water supplies. These electrons stick to the media and are unable to flow through the filter with water. They’re then flushed away in backwashing.
Another explanation of KDF purification technologies is that electrons are transferred between molecules and new elements are created – the impurities are changed into harmless elements.
What are the most common impurities that KDF can remove?
High-purity copper/zinc KDF media remove chlorine, copper, lead, mercury, chromium and other dissolved metals. It can also control microorganisms such as algae, fungi and bacteria in a water supply. Additionally, KDF controls scale and pH corrosion.
What can’t KDF media remove?
Though KDF can reduce and control microorganisms like bacteria, algae & fungi to some extent, viruses and cysts can’t be removed from the water with the oxidation/reduction chemical reaction. Additionally, while this type of filter can remove chlorine, it can’t remove other organic chemicals like pesticides and herbicides. Nitrates, fluoride, arsenic pharmaceuticals also can’t be removed from the water with this copper/zinc filtration.
Which is the best KDF media for me?
You need the media that effectively reduces or removes the impurities in your water supply, so if you don’t know what your water supply contains, that’s the place to start. Well water supplies should receive testing for microorganisms such as bacteria once a year, according to the EPA, while city water supplies are safe to drink but may contain traces of contamination, especially chemical impurities. You can use an at-home water testing kit to see what your water supply contains, which will help you to choose the best KDF media for the removal of these impurities. For instance, KDF 55 is best to remove chlorine and dissolved metals like nickel, chromium, lead & mercury, while KDF 85 is ideal for the removal of iron & hydrogen sulfide, and so on.