Three Stage Filter

Under the Counter – Three Stage Filter



Shown here is the three-stage filter that can be mounted or placed under the counter. The counter top version is similar with the canister holder reversed. The under the counter version comes with a facet, cold water connection and  connective tubing for easy installation. For installation instructions click here. There are two qualities of facets, the one shown is a low cost unit typical of an Reverse Osmosis system and the high cost unit shown below is specifically used with the Enagic Ionizer and is necessary for that application. We do offer installation for the under the counter version which is typically around $100.  To purchases either version click here.

It is called a three stage filter simply because there are 3 cartridges in the unit that the water is force through. Those three stages are the carbon block, the KDF, and the fluoride cartridge. Each has its unique function and there is some overlap between the carbon block and KDF. Read below more information on the filtering capability for each cartridge.

Cartridge Media Information

0.5 Micro Carbon Block

0.5 micro High performance carbon block cartridge. Removes chlorine, taste and odor, lead (particulate and dissolved), MTBE, VOCs, Giardia, Toxoplasma, Cryptosporidium and Entamoeba cysts, sediment and fine silt down to 0.5 microns. Rated at 20,000 gallons for chlorine,

Life span for carbon Block

2,000 for lead, 600 gallons for VOC, 500 for MTBE. Standard size cartridge (2 7/8″ X 9 3/4″) fits industry-standard housings.

Fluoride Cartridge

Contains fine-mesh per-conditioned Activated Alumina to reduce fluoride 95%+ on most city water (typically <2 ppm). Although the main purpose of this filter is to remove fluoride, Activated Alumina can remove many other contaminants


RemovesFluoride, Hydrogen Chloride, Hydrogen Sulfide, Carbonyl Sulfide, Carbon Dioxide, Inorganic Arsenic, Alcohols, Ethers. Design Flow Rate: .1 GPM, Weight: 2 lbs, Operation Temperature: 40°F to 100°F,  5,000 mg/L

Filter life span for fluoride cartridge

Approximately 4500 gallons with typical water concentration of fluoride

KDF 55

The Intelifil KDF 55 TM/Granular Activated Carbon Cartridges have superior taste and odor removal capabilities.  The copper granular KDF in this cartridge specializes in the removal of inorganic, heavy metals and chlorine.  This leaves the black granular coconut shell activated carbon free to do what it does best, removing organic matter. These filters last at least 5x more than standard carbon block filters. Standard size cartridge (2 7/8″ X 9 3/4″) fits industry-standard housings. KDF media controls scale, bacteria and algae, even in hot water. KDF media causes cellular damage to microbiological organisms, which can kill or inhibit any growth.


The water passes through a bed of a media made of a special high-purity alloy blend of two dissimilar metals – copper and zinc KDF-55D ®. This media, patented in 1987 by KDF Fluid Treatment, Inc., is a major advancement in water treatment technology that works on the electro-chemical and spontaneous-oxidation-reduction (redox) principles. Chlorine is instantaneously and almost inexhaustibly oxidized. Iron and hydrogen sulfide are oxidized into insolubable matter and attach to the surface of the media. Heavy metals such as lead, cadmium, and aluminum are removed from the water by the electro-chemical process. They are attracted to the surface of the media, much like a magnet. The media inhibits bacteria growth throughout the entire unit (in fact, has been shown to reduce it up to 90%!), eliminating the need for silver, commonly used in carbon-only filters (silver is considered a pesticide by the EPA and, as such, must be registered with them). Is copper or zinc added to the water in any significant amount? On 2.3 ppm chlorinated water <0.05 mg/l copper and only 0.46 mg/l zinc was measured. The EPA aesthetic levels are 1.0 mg/l for copper and 5.0 mg/l for zinc. And remember that both zinc and copper are essential minerals for good health – the FDA recommends a daily intake of 15 mg of zinc and 2 mg of copper.


Granulated activated carbon (GAC) is universally recognized and widely used as an effective adsorbent for a wide variety of organic contaminants, such as herbicides, pesticides, industrial chemicals, and trihalomethanes (THMs). Carbon is extremely porous and provides a large surface area for contaminants to collect (the surface area of the carbon in our filter would equal the surface of 50 football fields). Carbon-only filters must also use their capacity for chlorine removal, resulting in a shortened life. They also may use a bituminous coal carbon, which is good at removing chlorine, but not as effective at removing chemicals. We use a high-grade coconut shell carbon that is most effective at removing chemicals. Coconut shell carbon provides a significantly higher volume of micro pores than either coal-, wood- or lignite-based carbon. As a result, it is more effective than other carbon types in removing trihalomethanes (THMs) and other chemicals from municipally supplied water. Since the redox media removes the chlorine before it reaches the carbon, the carbon capacity is not wasted for chlorine and is free to concentrate more effectively on organic contaminants.

KDF life span for fluoride cartridge

Approximately 12,000 gallons with typical water concentrations