What is the difference between baking soda and soda ash for pools?

Baking soda (sodium bicarbonate) primarily raises total alkalinity with only a small effect on pH. Soda ash (sodium carbonate) primarily raises pH and also raises alkalinity as a secondary effect. Use baking soda when alkalinity is low but pH is in range. Use soda ash when pH is low.

Can I use baking soda to raise pool pH?

No — baking soda barely moves pH. It's designed to raise alkalinity. If you add baking soda to fix a low pH, you'll raise alkalinity well above the target range without solving the pH problem. The correct chemical to raise pool pH is soda ash (sodium carbonate).

How much baking soda do I add to my pool?

Roughly 1.5 lbs of baking soda raises total alkalinity by about 10 ppm in a 10,000-gallon pool. Always add less than you think you need, wait an hour, retest, and add more if needed. Overshooting alkalinity is harder to fix than overshooting on the low side.

How much soda ash do I add to my pool?

Roughly 6 oz of soda ash raises pH by about 0.2 in a 10,000-gallon pool when starting from pH 7.2. Soda ash is potent — start with half the calculated dose. It also raises total alkalinity as a side effect, so retest both pH and alkalinity after adjusting.

Should I use baking soda or soda ash first if both pH and alkalinity are low?

Add soda ash first. It raises both pH and alkalinity, so it solves two problems at once. If you start with baking soda, pH stays low — and when you then add soda ash to fix it, alkalinity climbs even higher. After soda ash brings pH into range, retest. If alkalinity is still low, then add baking soda to finish.

Can I use regular grocery store baking soda in my pool?

Yes. Arm & Hammer baking soda and generic store-brand baking soda are pure sodium bicarbonate — the same chemical pool stores sell as 'alkalinity increaser' at several times the price. Confirm the label says 100% sodium bicarbonate with no additives.

How long does baking soda take to work in a pool?

Most of the alkalinity change is visible within 30–60 minutes when the pump is running. Retest after at least one hour, and allow a full pump cycle (4–8 hours) before deciding whether to add more. Never add a second dose before retesting.

Part of: Pool Chemistry Basics Series

Baking soda vs soda ash for pools: which one do you need?

Q: Does baking soda lower pH in a pool?

No — baking soda slightly raises pH, not lowers it. To lower pool pH you need an acid: muriatic acid or dry acid (sodium bisulfate). Neither baking soda nor soda ash will bring pH down.

Q: Why does my pool get cloudy after adding soda ash?

Soda ash dissolves into a highly alkaline solution, which can briefly drive localized pH high enough to cause dissolved calcium to precipitate as fine calcium carbonate particles — a white haze. The cloudiness normally clears within a few hours as the filter runs. To minimize it, pre-dissolve soda ash in a bucket first and add slowly near a return jet.

6 min read · Updated June 3, 2026

Both are white powders that raise something in your pool. Both get tossed around in pool advice as if they're interchangeable. They're not. Baking soda raises alkalinity. Soda ash raises pH. Using the wrong one doesn't just fail to fix the problem — it makes your water chemistry worse.

The short answer: Use baking soda when your alkalinity is low but pH is in range. Use soda ash when your pH is low. Mixing them up is the most common mistake in pool chemistry — baking soda barely moves pH, and using it to chase a low pH ends up driving your alkalinity well above target.

Common brand names decoded

pH Up / pH Plus / pH Increaser = soda ash (sodium carbonate)
Alkalinity Up / Alkalinity Increaser = baking soda (sodium bicarbonate)
Pool stores charge 3–5× more for the same chemicals. Grocery store baking soda works identically.

What is soda ash for pools?

Soda ash is sodium carbonate (Na₂CO₃) — a white powder pool owners use to raise pH. It's sometimes sold under the labels "pH increaser," "pH up," or "pH plus" at pool supply stores, but it's the same chemical you'd find in the laundry aisle as "washing soda."

What does soda ash do in a pool? Three things:

Raises pH. Soda ash dissolves into highly alkaline solution (pH ~11.3), so even a small dose pushes pool pH upward quickly. This is its main job.
Raises alkalinity as a side effect. Each pound of soda ash that raises pH also bumps total alkalinity by a smaller amount. Useful when both pH and TA are low; problematic if only pH is low.
Can briefly cloud the water. Soda ash reacts with calcium in solution and can precipitate calcium carbonate as a fine haze. The cloudiness usually clears within a few hours as the filter runs.

Soda ash is the right move when your pH is below 7.2. It is not the right move when pH is already in range and only alkalinity is low — that's what baking soda is for. The next section breaks down both chemicals side-by-side.

Why does my pool get cloudy after adding soda ash?

This is normal and temporary. Soda ash dissolves into a highly alkaline solution, and as it disperses it can briefly drive localized pH high enough to cause dissolved calcium to precipitate as fine calcium carbonate particles — a white haze. The cloudiness usually clears within a few hours as the filter runs and water circulates. To minimize it: pre-dissolve soda ash in a bucket of pool water first, and add the solution slowly near a return jet. If cloudiness persists beyond 24 hours, it's worth testing your calcium hardness — very hard water amplifies the effect. See why pool water turns cloudy for more causes.

What each one does

Baking soda (sodium bicarbonate) primarily raises total alkalinity (TA) with only a minimal effect on pH. Use it when your alkalinity is low but your pH is already in range. You can buy it at any grocery store — it's the same stuff in the orange box.

Soda ash (sodium carbonate) primarily raises pH, and it also raises alkalinity as a secondary effect. Use it when your pH is low. It's sold at pool supply stores, sometimes labeled "pH increaser" or "pH up." Soda ash itself has a very high pH — around 11.3 in solution — which is why even small doses raise pool pH effectively.

Side-by-side comparison

	Baking Soda	Soda Ash
Chemical name	Sodium bicarbonate	Sodium carbonate
Primary effect	Raises alkalinity	Raises pH
Secondary effect	Slight pH increase	Also raises alkalinity
When to use	Low TA, pH is fine	Low pH
Dosing	~1.5 lbs per 10,000 gal raises TA ~10 ppm	~6 oz per 10,000 gal raises pH ~0.2
Dissolves	Quickly	Quickly (can cloud water briefly)
Cost	Very cheap (grocery store)	Moderate (pool supply)

The common mistake

The most frequent error pool owners make is using baking soda to raise pH. It seems logical — baking soda is cheap, easy to find, and the internet is full of advice telling you to dump it in. But baking soda barely moves pH. Its main job is raising alkalinity.

If your pH is 7.0 and you add baking soda, your pH will barely budge while your alkalinity climbs well above range. Now you have a new problem: high TA that's going to keep pushing your pH up later and make it hard to control.

The simple rule

If your pH is low, you need soda ash. If your alkalinity is low, you need baking soda. Don't use one to do the other's job.

Does baking soda lower pH in a pool?

No — baking soda slightly raises pH, not lowers it. If your pH is high and you add baking soda thinking it will balance things out, you'll push pH higher while also spiking your alkalinity above range. To lower pool pH you need an acid: muriatic acid (hydrochloric acid) or dry acid (sodium bisulfate). Neither baking soda nor soda ash will bring pH down.

Decision guide

Your Readings	What to Add	Why
pH low + TA low	Soda ash first	It raises both pH and TA at the same time
pH fine + TA low	Baking soda	Raises TA without significantly affecting pH
pH low + TA fine	Soda ash (small dose)	Raises pH; watch TA since it will rise too
pH high + TA high	Neither — you need acid	Muriatic acid or dry acid to bring both down

pH and TA drift together over time. PoolChem Tracker logs both readings, spots the pattern before it becomes a problem, and tells you exactly which chemical to add and how much — baking soda or soda ash, not just "add something." Track yours →

Why order matters

When both pH and alkalinity are low, it's tempting to reach for baking soda first since it's cheaper. But that's the wrong move. Soda ash raises both pH and alkalinity, so it solves two problems at once. If you start with baking soda, you'll raise TA but pH will still be low — and then when you add soda ash to fix pH, you'll push TA even higher.

The correct order: always address pH first with soda ash. After pH is in range, retest alkalinity. If TA is still low, then add baking soda to bring it up the rest of the way.

How to add each one

Pre-dissolve in a bucket of pool water before adding to the pool. This prevents clumping and ensures even distribution
Add near a return jet with the pump running so it circulates quickly throughout the pool
Wait at least 30 minutes before retesting. Give the water time to fully mix and the chemistry to stabilize
Don't add both on the same day. Adjust one, retest, then decide if you still need the other. Adding both at once makes it impossible to know what moved what

Can I use regular baking soda from the grocery store?

Yes. Arm & Hammer baking soda and generic store-brand equivalents are pure sodium bicarbonate — the exact same chemical the pool store sells as "alkalinity increaser" or "alkalinity up," typically at 3–5× the price. Check the label to confirm it's 100% sodium bicarbonate with no additives. Buying in bulk at a warehouse store is one of the easiest ways to cut pool chemical costs without changing anything about how you treat the water.

How long does it take for baking soda to work in a pool?

Most of the alkalinity change is visible within 30–60 minutes if the pump is running. Retest after at least an hour, and let the water fully circulate through one full pump cycle (typically 4–8 hours) before making a final decision on whether to add more. Soda ash works faster since it dissolves more readily, but the same guidance applies — retest before adding a second dose.

Dosing tip

Always start with less than you think you need. It's much easier to add more of either chemical than to correct an overshoot. Add half the calculated dose, wait an hour, retest, and add more if needed. Use the baking soda calculator or muriatic acid calculator to find your starting dose.

Know exactly what to add

PoolChem Tracker tells you whether you need baking soda or soda ash — and exactly how much — based on your current readings and pool size.