poolchemistrycalc

Raise pH

Into 21,100 gal of water, add

6.33lb 2.87kg

HASA Soda Ash — sodium carbonate, 100.0%. pH from 7.2 pH to 7.5 pH.

pH on one scale: the band 7.2–7.8, the ideal band 7.4–7.6, the reading now at 7.2 pH, and an arrow to 7.5 pH carrying 6.33 lb. reads now 7.2 pH target 7.5 pH ideal code 7.2 7.4 7.6 7.8 6.33 lb +0.3 pH with HASA Soda Ash

Your pool

feet, the long side
feet
inches of water, not wall height
inches of water
what your kit reads
where you want it

The quantity, the drawing, every product row and every step on this page are worked again as you type.

At 21,100 gal

Every product that does this

This product makes the whole change of +0.3 pH on its own.
Product Add Also moves
HASA Soda Ash
sodium carbonate 100.0% 		6.33 lb
2.87 kg		 +34.0 ppm
total alkalinity

The HASA Soda Ash label says: “1 lb for 10,000 gallons of water - raises pH by 0.1”.

In steps, if you would rather

Split into 5 equal steps of 1.27 lb each: add one, run the pump, and test again before the next.

To reach Total added Also moves
7.26 pH 1.27 lb +6.8 ppm
7.32 pH 2.53 lb +13.6 ppm
7.38 pH 3.80 lb +20.4 ppm
7.44 pH 5.06 lb +27.2 ppm
7.50 pH 6.33 lb +34.0 ppm

Where the band comes from

Source Range
COMAR 10.17.01.45 A(1)
conventional pool 		7.2–7.8 pH
Florida 64E-9.004 (1)(d)1
conventional pool 		7.0–7.8 pH
COMAR 10.17.01.45 A(1)
spa or hot tub 		7.2–7.8 pH

Pool and spa rules are adopted and amended state by state, and most of the ranges here are written for public pools. Confirm every figure against the code your jurisdiction has adopted and against your own product label.

Other adjustments

Updated October 2026

Sources and dates

Ranges are quoted from the code named beside them, product strengths from the manufacturer's own product page, each retrieved on the date shown.

This site publishes calculated water volumes and chemical quantities for home pool and spa owners. It is not a health, safety or professional service, and it does not replace the instructions printed on the product you are holding. Not affiliated with, endorsed by or sponsored by HASA, Pyrock Chemical, Pentair, Hayward, Sonoma Hot Tubs, the Centers for Disease Control and Prevention, or any state health department. Product names are the trademarks of their owners and appear here only to identify the strength of what is in the container.