Alkalinity is defined as any compound with the ability to neutralize acidity. Although we generally think of alkalinity as being the carbon dioxide, bicarbonate, carbonate species, it also includes ammonia borate and even sulfate.

Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal.

Ammonia gas diffuses into the resin beads and then exchanges as ammonium ion. Hydrogen form cation resins have very high capacity for ammonia when regenerated with acid.

Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal.

Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal.

Boron is a chemical element with symbol B and atomic number 5. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.

The hardness ions, calcium and magnesium, are most commonly removed by strong acid cation resins. These resins are regenerated using sodium chloride.

Cesium-137 removal is of utmost importance in both nuclear power plant operation and nuclear disaster waste stream treatment.

Chlorine is a chemical element with symbol Cl and atomic number 17. It is an extremely reactive element and a strong oxidising agent. Chlorine is normally present in water as hypochlorous anion and is removed by strong base anion resins.

Chromium is a chemical element with symbol Cr and atomic number 24. It is a steely-grey, lustrous, hard and brittle metal. Dissolved chromium may be cationic (tri chrome) or anionic (hex chrome) depending on pH and redox potential.

Copper is a chemical element with symbol Cu and atomic number 29. Copper is an essential trace nutrient and an extremely useful metal. Copper primarily forms a divalent cation in water.

Fluorine is a chemical element with symbol F and atomic number 9. Fluoride is deliberately added to most potable water supplies in the USA at a concentration of 1 mg/L to promote oral health.

Iron is a chemical element with symbol Fe and atomic number 26. It is the fourth most common element in the Earth's crust. Ferrous iron can be removed by a variety of cation resin.

Lead is a chemical element with atomic number 82 and symbol Pb. It is a soft, malleable, and heavy metal. Lead is the heaviest stable element.

Mercury is a chemical element with symbol Hg and atomic number 80. Mercury is a potent neurotoxin. Most mercury in our environment currently comes from coal fired power plants.

Strong base anion resin have good affinity for nitrate. The higher amines (triethylamine, tributylamine, etc.) have increased affinity for nitrate and decreased affinity for divalent ions such as sulfate, making them preferred for many applications.

Perchlorate is a relatively weak oxidant, used as an oxygen source in rocket fuel. Perchlorate is also a contaminant in ammonium nitrate fertilizers.

Radium is a chemical element with symbol Ra and atomic number 88. All isotopes of radium are highly radioactive. Radium is the daughter product of uranium decay.

Selenium is a chemical element with symbol Se and atomic number 34. While selenium is an important trace nutrient, high concentrations of selenium salts are toxic.

Sodium is a chemical element with symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is the sixth most abundant element in the Earth's crust.

Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series. Uranium has the highest atomic weight of the primordially occurring elements.

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is an essential trace nutrient and is the only supplement proven to help prevent colds. Zinc compounds are generally non-toxic.