total alkalinity

As stated before, total alkalinity tells you how many alkaline substances are in the water. In pool or spa water, this should be the alkalinity of bicarbonate. You want to have the alkalinity in a range of 80 ppm to 120 ppm.

Alkalinity measures the resistance of water to changes in pH. This is done through the presence of the carbonate family of ions. It should have enough carbonate ions to stabilize the pool chemicals, but not so many that scale will form.

Under ideal pool conditions (pH between 7.2 and 7.6), most of the carbonate is in the form of bicarbonate with a small amount of carbonate ions to provide saturation. When total alkalinity is measured with your test kit or test strips, it is considered for practical reasons to be equal to carbonate alkalinity.

If you add soda ash (soda ash) to the pool water, it will increase the total alkalinity because you will add carbonate ions, but it will cause wide variations in pH and it will be more difficult to control the pH. If you use baking soda, it will also increase the total alkalinity, but won’t change the pH much. If you need to add a large amount of baking soda, you should do so at the rate of about 2 pounds of chemical per 12,000 gallons of water every 3 to 4 days.

1.5 pounds of baking soda will raise the total alkalinity about 10 ppm in 10,000 gallons of water. So, to increase the total alkalinity of a 25,000-gallon pool to 10 ppm, you’ll need 3.75 pounds of baking soda. And to raise a 2,200-gallon spa at 10 ppm, you’ll need about 1/3 pound of baking soda.

Raising total alkalinity can be a time-consuming process, but once you’ve accomplished it, it usually won’t change much over time in a well-maintained pool. It is important that you adjust the alkalinity before adjusting the pH as it has a big effect on the pH and how it behaves.

While total alkalinity should generally be between 80 ppm and 120 ppm for pH buffering and carbonate saturation, the lower end is better for spas and the higher end for gypsum pools. If it is too low, it will cause etching in plaster puddles, metal corrosion, and eye irritation due to unstable pH. If it is too high, it can lead to a cloudy pool, increased use of acid to adjust pH, and a loss in chlorine efficiency.

Since lowering total alkalinity is also a slow process of slowly adding acid to the pool, it’s best to slowly bring the pool up to the correct level so it doesn’t “overshoot” where you want it to be. adjusted, you can now proceed to adjust your pH to the required 7.2 to 7.6. Adjusting the pH will be your second step in optimizing your pool chemicals.