Awesome Alkalinity
You may be familiar with the recent trend to drink alkaline water. This water has a pH (we learned about pH last month) higher than neutral and contains minerals like calcium and magnesium. It is suggested that these minerals can neutralize body acid, assist in hydration, and support bone health. Those with acid reflux often praise the effects of alkaline water. Pool water chemistry also relies on proper alkalinity.
About Alkalinity
Alkalinity is the capacity of water to neutralize acids and act as a buffer to stabilize pH and resist changes. Alkalinity is comprised of bicarbonates, carbonates and hydroxides. It is measured in parts per million (ppm) of calcium carbonate, rather than on the pH scale. If you think of alkalinity in football terms, we will assume the pH is the quarterback and the alkalinity is the offensive line. When the quarterback (pH) is protected by the offensive line (alkalinity), it has the ability to do its job. When it is lacking (or is out of balance), it is unable to perform its job and either runs around (pH bounce) or can’t move at all (pH lock). Additionally, if the cyanuric acid level is above 100 ppm, it can affect the alkalinity reading and its effectiveness. The ideal level for total alkalinity is between 80 and 120 ppm (mg/L). When we are using disinfectants with a high pH level (sodium hypochlorite and calcium hypochlorite), we want to keep the range between 80-100 ppm. When we are using disinfectants with a low pH (trichlor, dichlor), we want to keep the alkalinity range between 100-120 ppm (mg/L)
Allover Alkalinity
pH and Alkalinity have a tight relationship. With alkalinity being the anchor for pH, if it is out of range, it can dramatically impact pH. When the alkalinity is low and we experience pH bounce, the pool water can become out of balance. This can lead to ineffective sanitizer operation, etching of pool/spa surfaces, staining of surface walls, heater failure and/or eye/skin irritation. When the alkalinity is high, we can experience pH Lock. This can lead to cloudy water, rough pool/spa surfaces, clogged filters, clogged heater elements and reduced circulation. This can cause scaling on the surface and in the piping. To increase total alkalinity, we are going to add some sort of base, such as sodium carbonate or bicarbonate. To decrease, alkalinity can be lowered by the addition of acid, such as muriatic acid or sodium bisulfate. The same factors that affect the pH in the pool affect alkalinity. That is why we want to remove as much environmental debris as possible and shower before using the pool.
