Pool pH Adjustment with Borax

Overview

This guide explains how to accurately raise low pool pH using borax, including detailed testing steps, dosage calculation, and safe application.

Use a quality test kit (e.g., Taylor K2005) to measure current pH and total alkalinity.
Fill the test tube to the 44 ml line for pH testing, add 5 drops of R-4 reagent, shake, and read the result.
The example pool tested at a pH of about 7.0.
Measure alkalinity by filling to the 25 ml line, adding 2 drops of R-7 and 5 drops of R-8, then add R-9 drops while swirling until the color changes to get the alkalinity reading.
Example alkalinity result was 90 ppm, which is in the ideal range.

Use pure borax (sodium tetraborate) with no additives; 20 Mule Team is a common brand.
Borax is typically found in the laundry section of grocery stores.

Dosage depends on both pool volume and current alkalinity.
Use an online pool calculator to accurately determine how much borax is needed for your specific pool and test results.
For a 17,000-gallon pool with pH 7.0 and alkalinity 90 ppm, raising pH to 7.4 requires 107 ounces (about 6 pounds) of borax.
Higher alkalinity requires more borax to achieve the same pH increase.

Slowly pour calculated borax amount into the pool’s skimmer with the pump running.
In the example, one box (4 lbs 12 oz) plus an additional 16 oz (totaling almost 6 lbs) was added.

After adding, allow the pool to circulate, then re-test pH to ensure it has reached the target (about 7.4 in the example).
Borax safely raises pH with less impact on alkalinity than soda ash, making it easier to control adjustments.