Definition: . Alkalinity is important because it protects or buffers against rapid pH changes. Alkalinity measures the concentrations of bicarbonate, carbonate, and hydroxide ions and is expressed as an equivalent concentration of calcium carbonate (CaCO3).
Benefits of drinking alkaline water
Most sources of natural water contain dissolved minerals such as calcium and magnesium, which raise the pH of the water: these minerals and others important to our overall health. When your water is treated (disinfected) by the municipal water plant they add a number of chemicals including chlorine, alum and lime which alters the pH of the water.
Note re: Water Softeners: Conventional water softeners utilize ion exchange resin to remove calcium, one of the beneficial minerals, and replace it with the sodium which increases the salt content in your water. Water softeners waste between 100-1200 gallons of water per week, subject to the number of cycles required to recharge the resin (the harder, or more alkaline, the water the more cycles are required to recharge the resin).
Note re: Reverse Osmosis: Under sink reverse osmosis units are utilized to remove the salt added by the water softener; in addition to removing the salt they remove up to 90-95% of all the other beneficial minerals causing the water to become acidic (pH <7.0). Reverse osmosis units waste up to three (3) gallons of water for every one (1) gallon of water filtered.
Ideal range: The ideal range of alkalinity depends on the application. Rainwater and distilled water have an alkalinity of <10 mg/L CaCO3, seawater has an alkalinity of 3-500 mg/L CaCO3 while ground water can range from 50 to 1000 mg/L CaCO3.
Method of measurement: Alkalinity measures the capacity of water to neutralize acids.Total alkalinity is measured by collecting a water sample, and measuring the amount of acid needed to bring the sample to a pH of 4.2. At this pH all the alkaline compounds in the sample are "used up." The result is reported as milligrams per liter (mg/l) of calcium carbonate.
Method of control: Alkalinity can be adjusted by adjusting the pH and/or increasing the hardness of the water (see pH and hardness control).
*Note: Alkalinity and Hardness Relationship
Alkalinity and hardness are related through common ions formed in aquatic systems. Specifically, the counter-ions associated with the bicarbonate and carbonate fraction of alkalinity are the principal ions responsible for hardness (usually Ca++ and Mg++). As a result, the carbonate fraction of hardness (expressed as CaCO3 equivalents) is chemically equivalent to the bicarbonates of alkalinity present in water (Burton Jr. and Pitt 2002) in areas where the water interacts with limestone (Timmons et al. 2002). Any hardness greater than the alkalinity represents noncarbonate hardness.
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