Borax vs. Baking Soda: Which One Does Your Pool Actually Need?

When you test your pool water and notice the pH or total alkalinity is out of whack, a trip down the chemical aisle can feel confusing. You see two common household names sitting side by side: Borax and Baking Soda.

While both are mild, mineral-based powders used to adjust pool chemistry, they do completely different jobs. Using the wrong one for your specific water imbalance can throw your pool further out of whack.

Here is a look at what each chemical does, why they are not interchangeable, and how to know which one your pool actually needs.

1. Baking Soda: The Alkalinity Anchor

Baking soda (chemically known as sodium bicarbonate) is your pool's primary tool for managing total alkalinity.

• What It Does: Total alkalinity acts as a chemical buffer for your pool. It prevents your pH levels from bouncing wildly up and down when it rains, when organic debris falls in, or when swimmers get in the water.
• When to Use It: If your test kit shows that your total alkalinity is low (typically below 80 ppm), baking soda is the exact chemical you need. Because it has a near-neutral pH (around 8.0 to 9.0), adding it will raise your alkalinity safely without causing a massive, unmanageable spike in your pH.

2. Borax: The pH Booster

Borax (sodium tetraborate) is primarily used in pools to raise your pH levels without dramatically altering your total alkalinity.

• What It Does: If your pool water becomes too acidic (pH dropping below 7.2), it can corrode your metal equipment, etch your plaster, and sting swimmers' eyes. Borax gently pulls your pH back up into the ideal, comfortable range of 7.2 to 7.6.
• When to Use It: Use Borax when your pH is low, but your total alkalinity is already sitting comfortably in the correct range.

The Big Difference: Why You Can't Swap Them

The most common mistake pool owners make is treating Borax and Baking Soda as interchangeable quick-fixes.

• If you have low alkalinity and low pH: Baking soda will help raise both simultaneously, making it the more efficient choice.
• If your alkalinity is fine, but your pH is crashing: Borax steps in to raise the pH without unnecessarily driving your alkalinity up past recommended limits.
• The Borate Bonus: Some pool owners also add specific borate compounds to act as a mild algaestat and keep water feeling exceptionally soft, but routine adjustments rely strictly on identifying whether you are correcting pH or alkalinity.

Diagnose Before You Dose

Before pouring any powder into your pool, always rely on an accurate water test to check both your pH and total alkalinity. Matching the right chemical to the specific imbalance keeps your water sparkling, comfortable, and protective of your pool equipment.

Tired of guessing your chemical readings or trying to balance tricky water chemistry? Our professional pool service team is always here to handle precise testing, balancing, and maintenance so your backyard oasis stays pristine all year round!

‍