As mentioned earlier, the pH balance should be maintained between 7.2 and 7.8. According Executive Blue Pools, pH balance is the single most important factor in maintaining the correct chemical balance throughout your pool. When too low, the water is considered corrosive due to the damage it can cause to pool equipment. This corrosive water also causes chlorine destabilization, reducing free chlorine levels. If the pH level is above 7.8, the water can become cloudy and cause scales to form around the edges of the pool that eventually turn black. The filter can become clogged and destroyed. Not only that, but high pH also reduces the effectiveness of chlorine and will force you to use a lot more of it.
Believe it or not, Arm and Hammer says you can use baking soda to maintain pool pH! You can buy it in large quantities for pool maintenance, only it is called sodium bicarbonate. By using this simple household product instead of commercial pool products, you will save a lot of money. Baking soda raises the pH when it gets low and raises the alkalinity, which should be between 110 ppm and 150 ppm. If the alkalinity gets low, especially at 80 ppm or lower, you will add 1.5 lbs. of baking soda per 10,000 gallons of water by simply spreading it in arcs over the surface. Once it has dispersed, turn on the pool circulator and wait at least six hours before retesting. These steps can be repeated until the pH is 7.2 or higher and the alkalinity is at the desired level.