In a 1,000 gallon pool with alkalinity 80, about 0.83 fl oz (25 mL) of 31.45% muriatic acid lowers pH from 7.8 to 7.5. Acid demand rises with alkalinity, so use the calculator below with your TA. For alkalinity, 2.6 fl oz (76 mL) lowers TA by 10 ppm.
| Change | 31.45% acid | 14.5% acid |
|---|---|---|
| pH 7.8 → 7.5 | 0.83 fl oz | 1.9 fl oz |
| pH 8.0 → 7.5 | 1.2 fl oz | 2.8 fl oz |
| pH 8.2 → 7.6 | 1.1 fl oz | 2.7 fl oz |
| pH 7.7 → 7.4 | 0.99 fl oz | 2.3 fl oz |
| Lower alkalinity | 31.45% acid | 14.5% acid |
|---|---|---|
| TA −10 ppm | 2.6 fl oz | 6 fl oz |
| TA −20 ppm | 5.1 fl oz (2 parts) | 12 fl oz |
| TA −30 ppm | 7.7 fl oz (3 parts) | 18 fl oz |
Add
0.82fl oz
of Muriatic acid 31.45%
24 mL1¾ tbsp
Lowers pH from 7.8 to 7.5 in 1,000 gal at TA 80. TA afterwards: about 77 ppm.
Check the product label. Strengths vary by brand, so enter the % printed on yours. Add one chemical at a time, into the water, and never mix chemicals.
Save this test and get reminded when it is time to retest.
Pool Calc for iPhoneComing soon to the App StoreWear goggles and gloves, open the jug outdoors and stand upwind. With the pump running, pour the acid slowly in front of a return jet, low over the water. Always add acid to water, never water to acid.
Keep each addition to about 3.2 fl oz in this pool (12.5 ppm of alkalinity), then let it circulate for 30 minutes and retest pH. Bigger single doses can etch plaster and damage equipment near the return.
Never add acid and chlorine at the same time or in the same spot. Mixing them releases chlorine gas.
A 1,000 gallon pool is usually a large inflatable, a stock tank or a small frame pool. Doses this small are easy to overshoot: one extra splash is several ppm. Measure muriatic acid with kitchen measures you keep only for pool chemicals, and test after every addition.
Small pools also lose chlorine fast on sunny days because there is so little water. Test daily, and when the numbers drift far off it is often quicker to drain and refill than to correct them.
To lower pH from 7.8 to 7.5 at TA 80, about 0.83 fl oz of 31.45% acid. To lower alkalinity by 10 ppm, 2.6 fl oz.
Wait until it has circulated, typically about 30 minutes with the pump running, and retest pH before swimming. Keep children and pets out of the water until pH is back in range.
Yes. It is the same acid at about half the strength, so you need roughly twice as much: 6 fl oz lowers TA 10 ppm in 1,000 gallons.