Total alkalinity is a measure of the total amount of dissolved particles in the water whose pH is higher than 7.0. Total Alkalinity (TA) should usually be kept at 80 – 120 ppm, though in high alkalinity waters this is often hard to achieve without resulting in an abnormally low pH. When your TA is low, the following can occur:

  • etching of the plaster, marbelite, marcite or tile grouting
  • corrosion of metal parts (pool heater, steps, scoop pole, etc.)
  • staining of the pool’s surfaces
  • green water
  • burning eyes and itchy skin
  • pH bounce (rapid fluctuations in pH)

Raising Low Total Alkalinity

Sodium bicarbonate (bicarb) will raise the TA without excessively raising the pH. You should try to increase the TA over a period of time, adding a maximum of 1 pound of bicarb for each 6,000 gallons of water. When the TA is too high, the following can occur:

  • pH keeps going up despite regular addition of pH-down
  • cloudy water
  • burning eyes and itchy skin
  • reduced chlorine efficiency resulting in algae growth

Lowering High Total Alkalinity

To lower a high TA, you should:

  1. turn off the pumps and allowing the water to settle
  2. slowly add the pH-reducer into one spot in the deep end of the pool
  3. allow the chemicals to “burn off” some of the alkalinity for 15 – 30 minutes
  4. turn the pumps back on and allow the water to mix thoroughly