Alkalinity should be adjusted before pH. Add chemicals in increments and test after each addition. Allow 4–6 hours before retesting.
Sodium Bicarbonate to Raise Alkalinity (1.5 lb raises TA by 10 ppm per 10,000 gal)
| Pool Volume | +10 ppm | +20 ppm | +30 ppm | +40 ppm | +50 ppm |
|---|---|---|---|---|---|
| 8,000 gal | 1.2 lb | 2.4 lb | 3.6 lb | 4.8 lb | 6.0 lb |
| 10,000 gal | 1.5 lb | 3.0 lb | 4.5 lb | 6.0 lb | 7.5 lb |
| 12,000 gal | 1.8 lb | 3.6 lb | 5.4 lb | 7.2 lb | 9.0 lb |
| 15,000 gal | 2.25 lb | 4.5 lb | 6.75 lb | 9.0 lb | 11.25 lb |
| 20,000 gal | 3.0 lb | 6.0 lb | 9.0 lb | 12.0 lb | 15.0 lb |
Muriatic Acid (31.45%) to Lower Alkalinity
| Pool Volume | -10 ppm | -20 ppm | -30 ppm |
|---|---|---|---|
| 10,000 gal | 20 fl oz | 40 fl oz | 60 fl oz |
| 15,000 gal | 30 fl oz | 60 fl oz | 90 fl oz |
| 20,000 gal | 40 fl oz | 80 fl oz | 120 fl oz |
Notes
- Lowering TA also lowers pH — aerate after acid addition to help pH recover.
- Add sodium bicarbonate by broadcasting around the pool perimeter.
- Wait 4–6 hours before retesting alkalinity.
Sources:
- Taylor Technologies — Pool/Spa Water Chemistry Reference