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 answer, the drawings, every reading and every table on this page are worked for the values in these fields, and worked again as you type. The questions further down are answered for the example this page was published with.

At 21,100 gal

Every product that does this

Every product with a fetched strength that moves this reading by 0.3 pH. A row we can compute a quantity for comes first.
Product Add Also moves
HASA Soda Ash
sodium carbonate 100.0% 		6.33 lb
2.87 kg		 Total alkalinity
+34.0 ppm

The manufacturer's own dose sentence reads: 1 lb for 10,000 gallons of water - raises pH by 0.1. The figures above are computed from the product's strength.

In steps, if you would rather

One dose split five ways. Add a step, run the pump, and test again before the next.
To reach Add Total added Also moves
7.3 pH 1.27 lb 1.27 lb +6.8 ppm
7.3 pH 1.27 lb 2.53 lb +13.6 ppm
7.4 pH 1.27 lb 3.80 lb +20.4 ppm
7.4 pH 1.27 lb 5.06 lb +27.2 ppm
7.5 pH 1.27 lb 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 September 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.