Adsorption is a process of filtration that uses chemical processes to separate contaminants from water. Rather than simply physically blocking the passage of contaminants through the filter media, an adsorptive water filter utilizes particular types of filter media that will chemically attract contaminants and encourage them to break their bond with water molecules. Adsorption thus allows for the removal of more elusive contaminants, like chlorine, that are smaller in size than water molecules. Through the use of adsorption, water filters are able to selectively remove contaminants while retaining healthy mineral sediments.

Alachlor is an odorless, white, solid chemical, commonly used as an herbicide for grasses and other broadleaf plants. Alachlor is currently the second-most widely used herbicide in the United States. It has been used most heavily on corn and soybean crops in the midwestern states. Alachlor leaches into drinking water supplies through pesticide runoff. Short-term exposure to Alachlor can result in slight skin and/or eye irritation while long-term exposure to the chemical can cause eye, liver, kidney, or spleen damage, anemia, and increased risk of cancer. 

Atrizine is a white, solid, crystalline, chemical compound used as an herbicide for grasses and other broadleaf plants. Atrizine is the most commonly used herbicide in the United States, with use primarily occurring on corn and soybean crops in the Midwest. It makes its way into water as a result of pesticide runoff. Atrizine is highly toxic to the human body and can cause several health problems when ingested. Short-term exposure can result in low blood pressure, weight loss, and congestion of the heart, kidney, or lungs. Long-term exposure can cause cancer, damage to the cardiovascular system, and some muscle degeneration. 

Benzene is a highly flammable, colorless, and aromatic liquid that is often used in producing plastic, rubber, and synthetic fabrics like nylon and polyester. Benzene is also used as a solvent for printing and dry cleaning purposes. It most commonly occurs in drinking water as a result of industrial chemical spills. When ingested in water, Benzene can result in the short-term health effects of nervous system disorder, anemia, and immune system depression. The results of long-term exposure to Benzene include cancer and/or chromosome deviations.

Cryptosporidium: Cryptosporidium is a protozoan microbiological contaminant that is resistant to the disinfecting capabilities of chlorine. Ingestion of cryptosporidium generally leads to gastrointestinal illness.

Chlorine is a yellow-green, poisonous, gaseous compound with a pungent odor and a high potential for irritation. It is most often used as a water purification agent or as a bleaching and/or disinfection tool. When ingested in the liquid form, chlorine can lead to several types of cancer, including bladder, rectal, and breast cancer. When inhaled in the gaseous form, chlorine is a known cause and/or irritant of the respiratory conditions asthma and bronchitis. Chlorine can also cause severe skin irritations when absorbed dermally. 

The term cyst most commonly refers to the chlorine-resistant protozoa giardia and cryptosporidium. These microorganisms make their way into drinking water through human and animal fecal matter. Once in water, the protozoa form hard shells around themselves (cysts), making them resistant to the disinfecting capabilities of chlorine. Ingestion of cysts generally leads to severe gastrointestinal illness with symptoms of diarrhea, vomiting, and cramps. While these cysts are generally not present in drinking water, a breakdown in a municipal sanitation department could result in wide-scale contamination of municipal water. 

A KDF-55 filter media consists of finely granulated copper and zinc alloys. The combination of these two alloys in the media allows the chemical reaction of redox (Oxidation-Reduction) to take place when water passes through the media. Redox involves the transfer of electrons between two molecules, changing these molecules into entirely different elements. In the KDF process, electrons are taken from harmful contaminants like chlorine and microorganisms. This loss of electrons changes contaminants into far less harmful, or even harmless, elements. For example, chlorine-- when it loses an electron in a redox reaction--is changed into the harmless, water-soluble chemical chloride. While there are several different KDF media, KDF-55 is designed to specifically remove or reduce chlorine, heavy metals, and microbiological contaminants.

When a KDF-55 filter media is used during the first stage of filtration (as is the case with the EQ-300) the life of the entire filter unit is greatly lengthened. Translation of water contaminants into harmless elements in the first stage reduces the amount of scaling and bacterial growth that will take place on the more expensive carbon filter media of subsequent stages. Also, the preliminary removal of contaminants allows the adsorptive process of the carbon media to focus on more harmful and elusive contaminants.

Lead is a heavy metal substance used in several types of piping and as an additive in paint. It most typically makes its way into drinking water through the corrosion of household plumbing systems or the erosion of natural deposits into surface water sources. Ingestion of lead in drinking water has both short-term and long-term effects. Short-term exposure to lead in adults can interfere with red blood cell chemistry and increase blood pressure. Long-term exposure can result in kidney failure and/or stroke. Lead ingestion in children can cause severe physical and mental developmental delays. 

Lindane is a white, crystalline powder that has been commonly used as an insecticide in small gardens or on cattle or lumber. It makes its way into drinking water sources as a part of pesticide runoff. As a chemical, Lindane is highly toxic to humans. The use of Lindane is now closely regulated, due to its toxicity. Short-term exposure to Lindane can result in high body temperature and respiratory illness. Long-term exposure can lead to liver and/or kidney damage. 

The EPA sets both maximum contaminant levels (MCLs) and maximum contaminant level goals (MCLGs) each year for more than 70 known water contaminants. The MCL of a particular contaminant is the amount of that contaminant that may be in drinking water before the EPA will take action. The MCLG of a contaminant is the amount of the contaminant in drinking water at which there are no tested health risks. While the EPA is fairly strict with its enforcement of the MCLs of each of its regulated contaminants, it rarely ever reaches its MCLGs. 

Methyl-t-butyl ether (MTBE) is a member of a group of chemicals generally called fuel oxygenates. MTBE is typically added to unleaded gasoline to reduce its carbon monoxide and ozone content. MTBE makes its way into drinking water through several sources, including leakage of underground storage tanks, fuel spills, emissions from marine engines, and, to a small extent, condensation of exhaust fumes. Because MTBE is a relatively new contaminant, the EPA is currently conducting tests to clarify the potential health effects of ingesting MTBE in drinking water. 

National Resources Defense Council: The National Resources Defense Council (NRDC) is a political action group that seeks to protect the environment and the nation’s natural resources.

The National Sanitation Foundation (NSF) is a non-profit, non-government organization designed to assess the safety of consumer products. The NSF focuses specifically on products related to food, water, indoor air quality, and the environment. It produces national standards of quality for such products. An NSF certification is currently the most highly sought after certification for water treatment products. The NSF is staffed by an educated team of scientists, engineers, chemists, and environmental health experts who are committed to ensuring safe, high quality consumer products.

The pH of a substance refers to its basic level of acidity or alkalinity. A pH of 7 is neutral, while a pH below 7 is acidic and a pH above 7 is basic. Generally, water that has been treated has an acidic pH, due to the removal of balancing mineral deposits in the water. Intake of such acidic water can actually rob the teeth and bones of valuable minerals, as these minerals must be taken from the body to neutralize the water. Water filters, by retaining mineral deposits in water, produce a more neutral water product that does not take minerals from the teeth and bones.

Phthalate: Phthalate is a chemical typically used in the production of plastic materials. When ingested in water, phthalate can lead to cancer, miscarriage, premature birth, and asthma.

Redox, or reduction-oxidation, refers to a chemical process in which electrons are exchanged from one element or material to another. Reduction is the loss of electrons while oxidation is the gain of electrons. Once electrons have been exchanged, the charge and particular chemical characteristics of the elements are changed. In water filtration, the redox process is used to change harmful chemical contaminants into less harmful elements, by either adding or taking electrons from the contaminants.

Synthetic organic chemical (SOC) is an umbrella term for a large number of man-made chemicals that make their way into drinking water. These chemicals include, but are not limited to, pesticides, phthalate, and chlorine byproducts. As our use of these chemicals increases, they are being increasingly discovered in drinking water. SOCs, because they are made up of such a wide variety of chemicals, differ in their effects on the human body. However, the most common result of SOC ingestion is cancer. SOCs can now be linked to at least four types of cancer.

TCE: TCE is a liquid chemical, similar to chloroform, that is often used as a degreasing agent. Ingestion of TCE in drinking water can lead to problems with the liver and increased risk of cancer.

THMs, or trihalomethanes, are chemical compounds that are formed as a result of a reaction between organic materials in drinking water and chlorine added as a disinfectant. THMs are one of the many byproducts of water chlorination. When ingested in drinking water, THMs can cause a host of physical problems. THMs are known carcinogens and leading causes of bladder and rectal cancer. THMs can adversely affect nervous system functioning, as well as trigger liver and kidney malfunctions. Ingestion of THMs in drinking water has also been linked to spontaneous abortion, or miscarriage, in pregnancy. 

Trichloroethylene (TCE) is a chloroform-like fluid that is often used as a degreasing agent for man-made metal parts and some types of textiles. TCE is most often colorless, but it can also be blue. It generally makes its way into drinking water from leakage of underground storage tanks. If ingested in drinking water, TCE can cause problems with the liver and increased risk of bladder and/or rectal cancer. 

The Underwriters Laboratories (UL) is an international, non-profit, non-government foundation set up to test safety and health risks of thousands of consumer products. The UL was formed in 1894 to limit the number of deaths, injuries, or property damage that came about as a result of faulty or dangerous products. Each year it publishes reports and certification about and for manufacturers and consumers. The UL mark on a product is currently one of the most valuable and sought after certifications available

Volatile organic chemical (VOC) is the umbrella term for a large number of synthetic chemicals found in drinking water. These chemicals were first discovered in drinking water in 1977 and have now been identified as present in the water of 33 states. VOCs make their way into water through a variety of sources, including septic system cleaning, weed and pest control, fumigation, and dry cleaning. When ingested, VOCs are known to cause cancer, adversely affect liver and kidney functioning, and disrupt nervous system performance. When inhaled or dermally absorbed, VOCs can severely irritate the tissue of the lungs and the ski