Soda ash, also called sodium carbonate (Na2CO3), is a workhorse chemical used to raise pool pH, fix dye into cotton fibers, make glass, and boost laundry detergents. You can buy soda ash at pool supply retailers such as Leslie’s Pool Supplies and Pinch A Penny, at big-box hardware stores such as The Home Depot and Lowe’s, at Walmart, at craft and dye specialists such as Dharma Trading Company, and on Amazon. This guide explains where to buy soda ash for every common use, how the product differs from bicarbonate, how much to use, and how to handle it safely.
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What Soda Ash Is (And Why It Is Not Baking Soda)
Soda ash is the common name for sodium carbonate, a white, odorless powder with a pH of roughly 11 when dissolved in water. Soda ash is strongly alkaline, highly soluble, and inexpensive, which is why the compound shows up in pool care kits, tie-dye instructions, soap formulas, and heavy-duty cleaning products. It is sometimes labeled “washing soda,” “soda crystals,” or “dense soda ash,” but the chemistry is the same.
The single most common mistake shoppers make is confusing soda ash with baking soda. Baking soda is sodium bicarbonate (NaHCO3) and has a much milder pH around 8.3. Sodium carbonate is far more basic and raises water pH aggressively; the bicarbonate mostly raises alkalinity with little pH movement. Swapping one for the other in a pool, dye bath, or soap recipe will not work. If a label says “Arm & Hammer Baking Soda” it is the bicarbonate. If the box says “Arm & Hammer Super Washing Soda,” it is the carbonate.
Top Picks: The Best Sodium Carbonate to Buy in 2026
The best product depends on the job. A 55-ounce box is right-sized for household laundry and occasional tie-dye projects, while a 5-pound or 50-pound bag makes sense for pool owners, candle and soap makers, or anyone fixing large batches of fiber-reactive dye. Our picks below prioritize purity (100% sodium carbonate with no additives), packaging that keeps moisture out, and retailers that ship quickly.
- Best Overall: Arm & Hammer Super Washing Soda, 55 oz — The household standard. Pure sodium carbonate, widely stocked at grocery and hardware stores, and inexpensive. Works for laundry boosting, general cleaning, small tie-dye projects, and homemade soap recipes. Check price on Amazon.
- Best for Pools: HTH pH Up, 5 lb pouch — Formulated specifically for swimming pool water and sold in a resealable pouch that resists clumping. A five-pound pouch is enough for several seasons of pH corrections on a typical backyard pool. Check price on Amazon.
- Best for Tie-Dye: Dharma Trading Soda Ash Fixer, 1 lb — The go-to choice for fiber artists. Dharma sells a high-purity dye fixative that dissolves cleanly and works with Procion MX and other fiber-reactive dyes. Sold directly through dharmatrading.com and also available on Amazon in smaller packs. Check price on Amazon.
- Best Bulk: Arm & Hammer Super Washing Soda, 50 lb bag — The right buy for candle makers, soap businesses, large pools, and anyone who uses more than a box a month. Sold through commercial and industrial suppliers and through Amazon third-party sellers. Check price on Amazon.
- Best for Soap Making: Essential Depot Sodium Carbonate, 2 lb — Food-grade labeling and guaranteed purity, which matters when you are formulating cold-process soap or natural cleaning products where trace impurities can discolor a batch. Check price on Amazon.
Where to Buy Soda Ash: A Store-by-Store Guide
Pool Supply Retailers
Pool stores are the most reliable brick-and-mortar source for soda ash. Leslie’s Pool Supplies stocks it under names such as “Leslie’s Alka Plus” and “Leslie’s pH Plus” in 5, 10, and 25-pound containers, and staff can match a product to the pool volume you give them. Pinch A Penny, concentrated in the Southeast and Texas, carries similar house-brand and name-brand options. Pool Supplies Superstore and In The Swim ship bulk buckets by mail. Expect pool-grade product to cost a premium per pound but to come with dosing charts on the label.
Hardware and Big-Box Stores
The Home Depot and Lowe’s both carry it in the pool and spa chemicals aisle during the swim season, typically under HTH, Clorox Pool&Spa, or store-brand labels. Availability drops in winter in northern stores, so order online if it is out of stock locally. Ace Hardware and True Value often stock it year-round for cleaning and laundry customers. Walmart carries the Arm & Hammer product in the laundry aisle at nearly every location and lists larger bags on walmart.com through its marketplace partners.
Grocery and Drugstore Chains
Large supermarkets such as Kroger, Safeway, Publix, and Whole Foods stock the Arm & Hammer 55-oz box in the laundry detergent section. Target carries it both in store and on target.com. If you only need a single box for laundry or a small craft project, the grocery aisle is the fastest option.
Craft and Dye Specialists
Dharma Trading Company is the gold standard for tie-dye and batik supplies and sells its fixer in 1-lb, 5-lb, and 50-lb sizes alongside Procion dyes. Sally Beauty stocks Rit Dye fixative kits that include a small pouch for home dyeing. Jacquard sells a branded dye activator through joann.com, Michaels, Blick Art Materials, and Amazon. Hobby Lobby occasionally carries smaller tie-dye kits with the fixer included.
Online and Bulk
Amazon is the widest selection, with pool, laundry, craft, and soap-making grades all in one search. Chewy stocks aquarium-safe versions for reef and cichlid tanks. For 50-pound or pallet quantities, industrial suppliers such as Uline, Grainger, and Duda Diesel ship food-grade and technical-grade sodium carbonate directly to businesses and serious hobbyists. Costco and Sam’s Club occasionally feature large boxes during pool season.
How to Choose: A Practical Buying Guide
Three things matter when buying: grade, quantity, and packaging. Grade is straightforward — pool-grade, laundry-grade, and technical-grade are all sodium carbonate and interchangeable for most uses. Food-grade and USP-grade cost more and are only necessary for consumables. Quantity should match a season of use; a 55-oz box covers most households, a 5-lb pouch covers a pool season, and 25-lb or 50-lb bags are for businesses and heavy dyers. Packaging matters because the powder absorbs humidity and cakes into hard bricks if left open; a resealable pouch or a sealed plastic bag inside a box is preferable to an unsealed cardboard carton in humid climates.
Check the ingredient panel before you pay. A trustworthy product lists only “sodium carbonate” or the trade name at 100% concentration. Products marketed as “pH Up” or “Alkalinity Plus” sometimes blend carbonate with sodium bicarbonate; that blend is fine for pools but less ideal for tie-dye or soap, where pure carbonate performs better. Related alkaline cleaners such as borax are useful for laundry but are not interchangeable in dye or pool applications.
Common Uses and How Much Soda Ash to Add
Swimming pools. Soda ash is the preferred chemical for raising pool pH when the reading drops below 7.2. The general rule is 6 ounces of soda ash per 10,000 gallons to raise pH by 0.2 points, but always test before and after dosing and add in small increments. For a standard 20,000-gallon backyard pool moving from 7.0 to 7.4, roughly 24 ounces (about 1.5 pounds) is typical. Pre-dissolve the powder in a bucket of pool water and pour it into the deep end with the pump running.
Tie-dye and batik. Fiber-reactive dyes such as Procion MX need an alkaline environment to bond with cellulose fibers. The standard soak is 1 cup of soda ash per gallon of warm water; pre-soak cotton, rayon, or linen for 15 to 20 minutes before applying dye. Skipping this step is the most common reason homemade tie-dye bleeds and fades after the first wash.
Laundry boosting. Add a half-cup of soda ash to a regular wash load to soften hard water, lift grease, and brighten whites. It also boosts the effectiveness of powdered detergents, especially for cloth diapers and gym wear. Pair it with a splash of cleaning vinegar in the rinse cycle for extra deodorizing, but never mix the two in the same cycle, because the acid neutralizes the base.
Soap making. Cold-process makers use small amounts to harden bars, and crafters often deal with unwanted surface bloom on finished soap by steaming or covering bars during cure. Glass artists, pottery glaze makers, and photographers using classic developers also keep the carbonate in their supply cabinets.
Safety and Handling
Soda ash is not toxic the way pool chlorine or lye is, but its high pH makes it an irritant. Dry powder can cause skin dryness, and the dust irritates eyes and airways. Wet solutions above roughly 1% concentration can cause stinging and, with prolonged contact, mild chemical burns on sensitive skin. Children, pets, and anyone with respiratory conditions should stay clear of the bucket while you mix.
Follow these basic precautions adapted from OSHA and manufacturer safety data sheets:
- Wear nitrile gloves and splash-resistant eye protection when scooping or dissolving more than a cup at a time.
- Work in a ventilated area and avoid inhaling airborne powder; a dust mask is sensible for bulk bags.
- Always add the powder to water, not water to the powder, to limit splashing.
- Rinse immediately with cool water if any gets on skin or in eyes; seek medical attention for eye exposure.
- Store in a sealed container in a dry place, away from acids and out of reach of children and pets.
Frequently Asked Questions
Is soda ash the same as baking soda?
No. One is sodium carbonate (Na2CO3) with a pH near 11; the other is sodium bicarbonate (NaHCO3) with a pH near 8.3. They are different chemicals and are not interchangeable in pools, tie-dye, or most soap recipes.
Can I use baking soda instead of soda ash in my pool?
Not effectively. Bicarbonate raises total alkalinity with little effect on pH, while the carbonate raises pH strongly. Use bicarbonate to raise alkalinity when it drops below 80 ppm, and use the carbonate when pH drops below 7.2.
Why does tie-dye need soda ash?
Fiber-reactive dyes bond with cellulose fibers only in an alkaline environment. Soaking fabric in an alkaline solution raises the pH of the fiber so the dye forms a permanent covalent bond instead of washing out.
How much soda ash do I need for a 10,000-gallon pool?
About 6 ounces of soda ash raises the pH of 10,000 gallons by roughly 0.2 points. Always test first, add in small doses, and re-test after the pump has circulated the water for at least an hour.
Is Arm & Hammer Super Washing Soda the same as sodium carbonate?
Yes. Arm & Hammer Super Washing Soda is 100% sodium carbonate. It is the household grocery equivalent of the pool-store and craft-store versions, and works for laundry, cleaning, and small dye projects.
Bottom Line
For a single box for laundry or a small craft project, buy the Arm & Hammer product at any grocery store, Walmart, or Target. For pool pH correction, buy HTH or a store brand at Leslie’s Pool Supplies, The Home Depot, or Lowe’s. For tie-dye, order a purpose-made fixer from Dharma Trading Company. For bulk soap making or frequent use, buy a 25- or 50-pound bag from Amazon or an industrial supplier. Whatever the use, confirm the label reads 100% sodium carbonate, handle it with gloves and eye protection, and store it sealed in a dry place.