Question

Calculate the amount of NaHCO3 needed to raise the pH of a pool from 6.8 to 7.6.

NOTE: Pool volume is 2300 m^3

Answer 1

As a general rule 175 grams of sodium carbonate will raise the pH of an approximately 42,000 litres of water, by 0.1.

Na2CO3 needed to raise the pH by 0.8 (6.8 - 7.6)

= (175 *8g Na2CO3 / 42000 litre) * (2300000 litres)

= 76666.67 g Na2CO3

Baking soda (sodium bicarbonate) is only about half as efficient at raising pH.

Baking soda = 38333.33 g

Baking soda not only raises the pH, it also raises the total alkalinity. What that means in practice is that you should only use baking soda to raise pH when the total alkalinity is significantly below its desired range of 80-120 ppm. If the total alkalinity is close to or within the 80-120 ppm range, the danger is that baking soda will over-raise the total alkalinity: and then you suddenly be two chemical levels out of whack instead of just one.