PooloraHow much baking soda to add to a pool
Baking soda raises total alkalinity with very little change in pH. Here is how much for your pool size, in ounces and pounds.
- 15,000 gallons, alkalinity +10 ppm: 2.1 lb (34 oz · 955 g) of baking soda.
- Target 80–100 ppm with liquid chlorine, bleach, cal-hypo or salt; 100–120 ppm with tablets.
- Big doses go in two or three parts.
Chart: baking soda by pool size
| Pool size | +10 ppm | +20 ppm | +30 ppm |
|---|---|---|---|
| 5,000 gal | 11 oz 320 g | 1.4 lb 635 g | 2.1 lb 955 g |
| 10,000 gal | 1.4 lb 635 g | 2.8 lb 1.25 kg | 4.2 lb 1.9 kg |
| 15,000 gal | 2.1 lb 955 g | 4.2 lb 1.9 kg | 6.3 lb 2.85 kg |
| 20,000 gal | 2.8 lb 1.25 kg | 5.6 lb 2.55 kg | 8.4 lb 3.8 kg |
| 25,000 gal | 3.5 lb 1.6 kg | 7 lb 3.2 kg | 10.5 lb 4.75 kg |
| 30,000 gal | 4.2 lb 1.9 kg | 8.4 lb 3.8 kg | 12.6 lb 5.7 kg |
Work out your dose
Subtract your reading from your target and read the chart. Example: a 15,000-gallon pool reads alkalinity 60 and you use liquid chlorine, so you aim for 90. That is +30 ppm: 6.3 lb (101 oz · 2.85 kg) of baking soda, added in two or three parts.
Added too much?
Alkalinity above your range makes pH creep up and acid less effective. Bring it down with acid and aeration; see how much muriatic acid.
Where to aim
The Pool & Hot Tub Alliance recommends 80–100 ppm when your chlorine pushes pH up (liquid chlorine, bleach, cal-hypo, salt systems) and 100–120 ppm with tablets, which are acidic. The absolute limits are 60–180 ppm (ANSI/APSP/ICC-11).
How to add it
- Spread it over the deep end with the pump running, or pre-dissolve it in a bucket of pool water.
- For more than about 10 ppm, add it in two or three parts and retest in between.
- Retest pH afterwards: if it was a little low, raising alkalinity may be all it needed.
Common questions
Can I use baking soda from the grocery store?
Yes, if the label says sodium bicarbonate and nothing else. Pool "alkalinity up" products are usually the same chemical.
Does baking soda raise pH?
Only slightly. To raise pH use soda ash or aeration; see how to raise pH.
Do it with your own products
Poolora turns your test into the exact amount of the products on your shelf, in cups and ounces, in the right order, and tells you when it's safe to swim. Free to start; every chemical, water balance and history are part of Pro.
Keep going
Sources
- Pool & Hot Tub Alliance (PHTA): alkalinity fact sheet
- ANSI/APSP/ICC-11 (TA 60–180 ppm)
- Doses: Poolora engine (mass balance by product and strength; pH by a carbonate-equilibrium model with constants from the USGS PHREEQC database)