Pool Baking Soda Calculator
Find out exactly how much baking soda to add to bring your total alkalinity into the ideal 80-120 ppm range. Works for pure baking soda and pool alkalinity increaser.
What Is Total Alkalinity and Why Should You Care?
Total alkalinity (TA) is the water’s ability to hold pH steady. Think of it as the anchor for your pH level. When TA is in the right range, your pH stays put. When TA is off, pH bounces around and makes balancing the rest of your water a headache.
The sweet spot for pool TA is 80 to 120 ppm. At 100 ppm you get the best pH stability without the side effects. Here is what happens when you drift outside that zone:
- Low TA (below 80 ppm) – Your pH becomes bouncy. A little rain, a few swimmers, and suddenly your pH drops. That can make the water corrosive, eating at plaster, grout, and metal fittings. Swimmers might feel eye or skin irritation from the sudden swings.
- High TA (above 120 ppm) – Your pH constantly drifts upward. You end up adding acid over and over. Scale builds up on pool surfaces and inside your pipes. Chlorine works worse because the pH creeps too high.
How Baking Soda Raises Total Alkalinity
Baking soda (sodium bicarbonate) is the go-to chemical for nudging TA up. It is cheap, found in every grocery store, and completely safe to handle. Pool stores sell the identical chemical as “alkalinity increaser” for a higher price.
The standard dosing formula used by pool pros: 1.5 lbs (24 oz) of baking soda per 10,000 gallons raises total alkalinity by 10 ppm. That breaks down to 2.4 ounces per 1 ppm in 10,000 gallons. The calculator above uses this exact math to give you the right amount for your pool, no guesswork needed.
Does baking soda raise pH too?
Yes, but not by much. Raising TA by 10 ppm with baking soda typically bumps pH up by about 0.05 to 0.1 units. It is a side effect, not the main job. If you need to raise pH significantly and TA is already fine, use soda ash (sodium carbonate) instead. Baking soda is for alkalinity first, pH second.
Baking Soda vs. Soda Ash: Do Not Mix Them Up
Both are white powders. Both come in bags. But they do very different things. Here is the quick way to remember:
| Product | Main job | pH effect | TA effect | Use when |
|---|---|---|---|---|
| Baking soda | Raises TA | Mild (0.05-0.1) | Strong | TA is low, pH may be slightly low |
| Soda ash | Raises pH | Strong (0.2-0.3) | Mild | pH is low, TA is already good |
Simple rule: both low? Fix TA with baking soda first, then re-test and adjust pH. Only pH low? Reach for soda ash.
How to Add Baking Soda to Your Pool Correctly
- Test your TA first. Strips or a drop test kit both work.
- Use the calculator above. Get the exact weight for your pool.
- Pre-dissolve in a bucket. Fill a clean bucket two-thirds with pool water. Add the measured baking soda while stirring. This stops clouding and helps it dissolve.
- Pour near a return jet. With the pump running, slowly pour the dissolved solution near a return. Walk around as you pour to spread it out.
- Keep the pump going for at least 6 hours. Full circulation takes time.
- Re-test after 6 to 24 hours. If TA is still under target, add the next portion. Never do the whole big adjustment at once if it is more than 50 ppm.
Quick Reference Dosing Table
| Pool size | To raise TA by 10 ppm | To raise TA by 20 ppm | To raise TA by 40 ppm |
|---|---|---|---|
| 5,000 gal | 12 oz (0.75 lbs) | 24 oz (1.5 lbs) | 48 oz (3 lbs) |
| 10,000 gal | 24 oz (1.5 lbs) | 48 oz (3 lbs) | 96 oz (6 lbs) |
| 15,000 gal | 36 oz (2.25 lbs) | 72 oz (4.5 lbs) | 144 oz (9 lbs) |
| 20,000 gal | 48 oz (3 lbs) | 96 oz (6 lbs) | 192 oz (12 lbs) |
| 25,000 gal | 60 oz (3.75 lbs) | 120 oz (7.5 lbs) | 240 oz (15 lbs) |
These are ballpark numbers for fresh baking soda. Use the calculator for your exact situation, especially if your current TA is not zero.
Why Your Total Alkalinity Changes Over Time
TA does not change as fast as pH, but it drifts. Here is what moves it:
What lowers TA
- Adding acid. Muriatic acid and dry acid both eat away at TA as they lower pH. This is the main way TA drops.
- Heavy rain. Rainwater is slightly acidic and dilutes your pool water.
- Lots of swimmers. Sweat, body oils, and organic waste are acidic and consume alkalinity.
- Trichlor tablets. These chlorine tabs are acidic and slowly chip away at TA over time.
What raises TA
- Adding baking soda. This is the main way to raise it on purpose.
- Fresh fill water. Many city water supplies come with TA already high (150 ppm or more).
- Some calcium products. Certain calcium hardness increasers also contain bicarbonates that nudge TA up.
How to Test Total Alkalinity
- Test strips. Dip and read. Good for quick checks each week. Most multi-test strips include TA.
- Liquid drop kit. Add reagent drops and count until the color changes from green to red. More accurate than strips. The Taylor K-2005 is the pick among pool owners.
- Digital meter. Dip the probe for an instant number. Most precise, but needs regular calibration.
Test TA once a week during swim season. Also test after heavy rain, after adding acid, and whenever you notice your pH acting unstable.
Common Questions
How much baking soda do I add to raise total alkalinity?
The standard is 1.5 lbs (24 oz) per 10,000 gallons to raise TA by 10 ppm. Use the calculator above to get an exact number for your pool size and current reading.
Can I use regular baking soda from the grocery store?
Absolutely. Regular baking soda is pure sodium bicarbonate, the exact same chemical sold as pool alkalinity increaser. Buying large bags or bulk boxes from the grocery is the cheaper route.
Will baking soda raise my pH?
It gives a small bump, about 0.05 to 0.1 units for every 10 ppm TA you add. If your pH needs a bigger jump, soda ash is the better tool. Baking soda is first for alkalinity.
What is the difference between baking soda and soda ash?
Baking soda raises TA with a mild pH lift. Soda ash raises pH with a mild TA lift. They are not interchangeable. Use baking soda when TA is low. Use soda ash when pH is low but TA is already where it should be.
How long after adding baking soda can I swim?
Wait about 30 minutes with the pump running if the dose was small and pre-dissolved. For larger adjustments (over 50 ppm TA), wait 6 hours and re-test before anyone gets in.
Why does my pool pH keep going up even though TA is fine?
If TA is 80 to 120 but pH still drifts up, the usual culprits are a salt chlorine generator (which pushes pH up as a byproduct) or water features like fountains and waterfalls that release CO2. In salt pools, keep TA at the lower end of the range (70 to 90 ppm) to reduce that upward pressure.
Can I add too much baking soda?
Yes. If TA goes above 120 ppm, pH starts its slow climb and becomes stubborn to adjust. The fix for high TA is muriatic acid plus aeration, a multi-step process. It is far easier to dose carefully from the start.
Is baking soda safe for saltwater pools?
Yes. Saltwater pools actually benefit from keeping TA in the 70 to 100 ppm range because the salt cell naturally raises pH. Baking soda can nudge TA back up if it ever dips below 70 ppm from acid additions or heavy rain.