Soda ash is sodium carbonate, and the cheapest place to buy it depends on how much you need. For one tie-dye session, a box of washing soda from the supermarket laundry aisle does the job. For a pool, buy the pool-store bag labeled pH Up. For soap, glaze, or a summer of dyeing, order a big bag, where the price per pound drops to roughly half of what a 1 lb packet costs. The chemical is the same in all three. The label, the packaging, and the price per pound are what change.
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What Is Soda Ash? Sodium Carbonate Under Four Labels
Soda ash is sodium carbonate (Na2CO3), an odorless white alkali used to raise pH, fix fabric color, boost detergent, and make glass. It is an inorganic compound, water-soluble, and strongly alkaline once dissolved. On a shelf it goes by four names: soda ash, sodium carbonate, washing soda, and (for the hydrated crystal form sold in the UK) soda crystals.
Most American supply is mined, not synthesized. It is refined from trona ore near Green River, Wyoming, the largest trona deposit in the world, and the U.S. Geological Survey publishes annual production figures. Its Mineral Commodity Summaries 2026 puts 2025 U.S. output at an estimated 12 million tons from four Wyoming companies running five plants plus one plant in California. About 1.8 tons of trona yields 1 ton of finished product. Outside the U.S., much of the world’s supply comes from the Solvay process, a production method that builds it from sodium chloride brine, limestone, and ammonia.
Retail buyers are a sliver of demand: the same report estimates 2025 end use at 45% glass manufacturing, 28% chemicals, 5% soap and detergents, and 1% water treatment. Four groups make up the household and hobby market:
- Pool and spa owners correcting low pH in swimming pools. It lifts pH harder than sodium bicarbonate and raises total alkalinity too.
- Tie-dye and batik artists who need an alkaline soak so fiber-reactive dyes bond to cotton and other cellulose fibers. Natural dyers also use it to scour cloth before a mordant.
- Laundry users fighting hard water. The carbonate ion reacts with dissolved calcium and magnesium and drops them out as insoluble carbonates, so detergent can foam and clean.
- Soap, pottery, and glass makers who need a strong base, a glaze flux, or the alkali in soda-lime glass alongside silica sand and limestone (calcium carbonate).
What It Costs per Pound, by Bag Size
Price per pound falls steeply with bag size, and the gap is bigger than most buyers expect. When we checked retailer listings on October 14, 2026, these were the posted prices for the pure powder:
| Product and size | Listed price | Per pound |
|---|---|---|
| Dharma Trading Soda Ash Fixer, 1 lb | $1.75 | $1.75 |
| Dharma Trading Soda Ash Fixer, 5 lb | $6.25 | $1.25 |
| Dharma Trading Soda Ash Fixer, 25 lb | $25.95 | About $1.04 |
| Leslie’s Soda Ash pH Up, 50 lb bag | $46.99 | About $0.94 |
Shipping is extra on all of these. For context, USGS puts the 2025 average value at the mine or plant at about 150 USD per metric ton, a few cents a pound. Everything above that is bagging, freight, and retail margin, so savings flatten out once you reach the largest bag a household can store.
Which Grade to Buy, and What the Label Must Say
Pool, laundry, and technical grades are the same chemical and work interchangeably for pools, cleaning, and fiber work. Food grade costs more for testing and paperwork, not for better results. Read four things on the bag and ignore the marketing.
- The ingredient line. It should list one chemical and nothing else. Sodium bicarbonate and sodium hydroxide are different chemicals. “pH Up” on the front is a claim, not a formula.
- pH increaser versus alkalinity increaser. Pool brands sell both, and the bags look alike. In The Swim, for example, sells a pH increaser made of soda ash and a separate Alkalinity Increaser that is 100% sodium bicarbonate. Only the first one is what you want.
- Light versus dense. Soda ash lite and dense grades are chemically identical but differ in bulk density, so a cup of one weighs less than a cup of the other. Dharma Trading says its dense fixer lets you use up to 25% less powder than diluted products. Measure by weight when a recipe is written in ounces.
- Packaging. The anhydrous powder pulls moisture from humid air and cakes into a brick. Pick a resealable pouch or bucket over a plain carton, or decant into an airtight jar.
| Grade or label | Typical use | Where it sells |
|---|---|---|
| Washing soda (laundry) | Wash boosting, cleaning | Supermarkets, Walmart.com |
| Pool pH increaser | Raising swimming pool pH | Leslie’s, home center pool aisles |
| Fixer (technical) | Tie-dye, batik, scouring | Dharma Trading, Jacquard dealers |
| Industrial bags | Soap, glass, big pools | Leslie’s, Univar Solutions, Waterline Technologies |
Where to Buy Soda Ash in Store
Local stock splits three ways: pool aisles in season, the laundry aisle year-round, and art or fiber suppliers for fixer.
Pool Supply Stores
Leslie’s sells its own Soda Ash pH Up in 5, 10, 45, and 50 lb sizes plus buckets, and the product page lists it as 100% sodium carbonate. Independent pool stores carry similar bags, and the same counter usually stocks filter media and boric acid.
Home Centers and Big-Box Stores
Home centers and hardware chains shelve pool pH increasers with the pool and spa chemicals (Ace Hardware, for one, lists HTH pH Up), and northern stores often shrink that section after summer, so check online inventory first. Walmart, the largest brick-and-mortar retailer in the United States, lists Arm & Hammer Super Washing Soda in the 55 oz box on Walmart.com, and store stock varies by location.
Supermarket Laundry Aisles
The laundry aisle is the fastest route to a single box, usually shelved near the borax. Arm & Hammer Super Washing Soda in the 55 oz carton is the common one, and grocery listings such as ShopRite’s show sodium carbonate as its only ingredient.
Craft and Fiber-Art Suppliers
Dharma Trading Company is the reference source for fiber artists, selling fixer beside its reactive colors and the blank fabric it goes on. Jacquard Products sells soda ash in 1 and 5 lb sizes direct and through art retailers such as Jerry’s Artarama. Pro Chemical & Dye, Botanical Colors, and Maiwa stock it for scouring and natural dyeing. One dead end: Jo-Ann closed its last stores in May 2025, and Michaels bought the brand name and private labels, not the stores.
Online and Bulk Sources
Online is the only practical route for bulk.
- Amazon, the largest online retailer in the United States, lists pool, laundry, craft, and food grades side by side, the easiest way to compare cost per pound.
- Walmart.com carries sizes that rarely reach a shelf, including In The Swim pH increaser and a 25 lb bag of Duda Energy dense soda ash, many through marketplace sellers who set their own return terms.
- Dharma Trading Company and Jacquard Products sell fixer direct; Dharma goes up to a 25 lb bag.
- Univar Solutions and Waterline Technologies, chemical distributors, list technical grade by the sack, the route soap makers and pool services use.
- The Ceramic Shop stocks it as a pottery glaze material.
How Much to Use: Label Doses for Fabric and Pools
These come straight from the sellers’ own directions:
- Tie-dye presoak: 1 cup per gallon of warm water (Jacquard and Dharma agree). Jacquard says soak 20 minutes, wring out, and do not rinse.
- Immersion dyeing: Jacquard uses 1/4 to 1/3 cup per 3 gallons of water; Dharma uses 1 oz per gallon for garment dyeing.
- Target pH for dyeing with fiber-reactive dyes: about 10.5, per Dharma, which suggests test strips.
- Silk and wool: Dharma says use half the cotton amount on silk and cure it only 4 to 6 hours, and it does not recommend soda ash on wool, which turns brittle.
- Pools: Leslie’s label says 1 lb per 10,000 gallons below pH 7.2, a 4 lb cap per dose, and 4 hours of circulation before swimming.
Mix-Ups and Safety Before You Open the Bag
The costliest mistake is not overpaying. It is buying the wrong white powder.
Baking soda is weaker. Sodium bicarbonate (NaHCO3) barely shifts pH by comparison. Swap it into a fixer bath and the color washes out.
Caustic soda is far stronger. Sodium hydroxide, sold as caustic soda or lye, is a much more aggressive hydroxide base that causes severe chemical burns. It is no substitute in a fixer bath or a pool.
Handle it like powdered bleach. Dharma calls it mildly caustic and recommends an N95 dust mask, gloves, and eye protection, and says to flush eyes with water for 15 minutes after contact. Add powder to water rather than the reverse, and keep it away from acids. It fizzes hard against citric acid or a cleaning vinegar such as Heinz Cleaning Vinegar, so never mix them in a sealed container.
Pool and craft grades are not food. A food-grade version exists as a food additive and acidity regulator, used in ramen noodles and by home bakers as a milder stand-in for lye on pretzels. Buy food grade, labeled as such, for that job.
Returns: Why an Opened Bag Rarely Goes Back
Assume the sale is final once the seal is broken. Leslie’s allows returns within 30 days only for unused items in original packaging, and its policy excludes online orders of hazardous materials, including acids and bases, which covers a shipped bag of soda ash. The Home Depot’s policy page gives most merchandise 90 days with proof of purchase, but unused and unopened is the safe assumption for any pool chemical. Marketplace sellers on Amazon and Walmart.com set their own terms, so read the listing before ordering a sack you might not use.
Top Picks by Job
These five are sorted by job rather than brand, since the powder inside is the same. Only prices we confirmed on October 14, 2026 are shown; check the live listing for the rest.
- Best overall: Arm & Hammer Super Washing Soda, 55 oz. The household standard, fragrance-free and phosphate-free, with sodium carbonate as the only listed ingredient. Covers laundry, cleaning, and a small craft project. Con: the carton does not reseal. Check price on Amazon.
- Best for pools: HTH pH Up. A resealable pouch with dosing directions on the label, the real reason to pay the pool-aisle premium. Confirm the ingredient line before you buy. Check price on Amazon.
- Best for tie-dye: Jacquard Soda Ash Dye Fixer, 1 lb. The fiber-artist default, sized for a batch of shirts rather than a pool, with presoak and immersion directions on the bag. Dharma Trading’s own 1 lb fixer is the direct-order alternative at $1.75. Check price on Amazon.
- Best for a busy dye studio: Jacquard Soda Ash, 5 lb. Enough for several group sessions, from a brand most art retailers stock. For frequent use, Dharma’s 25 lb bag is cheaper per pound. See it on Amazon.
- Best budget per pound: 50 lb bag. For soap makers, big pools, and anyone emptying a box a month. Leslie’s 50 lb pH Up bag listed at $46.99, under a dollar a pound. Con: fifty pounds needs dry storage. Compare bulk listings.
Start with the job, not the store. For cleaning or one craft project, grab a washing soda box from the supermarket laundry aisle. For pool pH, buy a pool-grade bag at Leslie’s or a home center and dose by the label and your test kit. For regular dyeing, soap, or glaze work, order a 25 or 50 lb bag and store it dry. Check that the ingredient line reads sodium carbonate, and the right soda ash will cost less than you expect.
Frequently Asked Questions
Is soda ash just baking soda?
No. One is sodium carbonate, the other sodium bicarbonate, and the carbonate is by far the stronger base. A carbonate solution sits near pH 11 while baking soda in water hovers around pH 8, which is why one moves pool water fast and the other stays in the kitchen. Heating baking soda converts it toward the carbonate, but inconsistently.
Is borax the same as soda ash?
No. Borax is sodium tetraborate, a separate compound and a much milder base that lands near pH 9 in solution. Both soften water and help detergent work, so they overlap in the laundry room, but borax will not reliably set fiber-reactive color or raise pool pH.
What can I substitute for it?
Washing soda is the direct substitute, because it is the same chemical. A 55 oz carton is about 3.4 pounds, plenty for a tie-dye session and nowhere near enough for a pool. Baking soda and borax are not substitutes for fixing color or pool pH, and caustic soda is too dangerous for either job.
How should I store it at home?
Keep it sealed and dry, because the anhydrous powder absorbs humidity and hardens. A lidded bucket or mason jar works for smaller amounts. It is not flammable, but the dissolved solution corrodes aluminum, so mix and store it in plastic or stainless steel, away from acids.
Which aisle is it in at the store?
Check the laundry aisle first, near the borax, where the box is labeled washing soda. Home centers shelve it with pool and spa chemicals, usually in season, and the label there normally reads pH Up rather than the chemical name. Art supply stores file it with fabric paints and colorants.
Reviewed by the wheretobuyguides.com editorial team. Retailer listings, prices, and return policies checked October 14, 2026.