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