Add
What total alkalinity does
Total alkalinity (TA) measures the buffers in your water, mainly bicarbonate. It keeps pH from bouncing around. Too low (under about 60 ppm) and pH swings with every rain or chemical addition; too high (over about 120 ppm) and pH keeps creeping up, so you are constantly adding acid.
A good range for most pools is 70–120 ppm. Saltwater pools and pools using trichlor tablets often do best at the lower end (60–80 ppm), because it slows the upward drift of pH. Plaster pools usually need the middle of the range (80–100 ppm) to protect the surface.
Raising alkalinity with baking soda
Baking soda (sodium bicarbonate) is the standard way to raise alkalinity, and it barely changes pH. About 1.4 lb per 10,000 gallons raises TA by 10 ppm. Grocery-store baking soda and "alkalinity increaser" are the same chemical. For big increases, split the dose: add up to about 10 lb per 10,000 gallons at a time, wait a few hours and retest.
Lowering alkalinity with acid and aeration
Acid lowers both alkalinity and pH. On its own, adding enough acid to lower TA a lot would crash your pH. The usual method is to add acid to bring pH down to about 7.2, then aerate the water so pH rises again without adding alkalinity, and repeat over several days. About 25.6 fl oz of 31.45% muriatic acid lowers TA by 10 ppm in 10,000 gallons.
Safety first: Always read the product label. Add chemicals to water, never water to chemicals. Add one chemical at a time with the pump running, never mix products (especially chlorine and acid), and keep everyone out of the water until levels are back in range. Wear gloves and eye protection when handling acid or shock.
Sources and methodology
Last reviewed: November 2026. Doses are calculated from the chemistry of each product (molecular weights and available chlorine) and cross-checked against manufacturer and industry dosing charts. Recommended ranges follow CDC guidance for home pools and hot tubs.
Frequently asked questions
How much baking soda raises alkalinity by 10 ppm?
About 1.4 lb of baking soda raises total alkalinity by 10 ppm in 10,000 gallons.
Is pool alkalinity increaser the same as baking soda?
Yes. Alkalinity increaser is sodium bicarbonate, the same as grocery-store baking soda, usually at a higher price.
How do I lower alkalinity without lowering pH too much?
Add acid to bring pH down to about 7.2, then aerate the water (fountains, jets pointed up, an air pump) to raise pH back up without adding alkalinity. Repeat until alkalinity reaches your target.