Borax In Your Pool: Everything You Need to Know


by Rick Patterson

Who could forget that old-timey box of borax underneath your grandparents’ kitchen sink? You may have used it to scrub the floors or tossed it in with your laundry from time to time. But did you know that borax can solve your pool’s tricky pH problems?

It’s been a cheap and hardworking cleaning product forever and now it’s flexing its pool care muscles. 

What Is Borax?

Borax, also known as sodium borate, sodium tetraborate, and disodium tetraborate, is a chemical compound of the element boron. It’s a chalky, white, powdery substance that is mainly known for its uses as a household cleaning agent.

Borax is a mineral and a salt of boric acid that can also be found in crystal or granular form. It shares many properties with generic table salt and is great not only for removing mold/mildew and getting your clothes whiter in the laundry but also as an insecticide and water softener. It’s also used to make homemade slime!

This jack-of-all-trades mineral has been helpful around the house for decades but does it have a place in your pool too? Let’s find out.

20 Mule Team All Natural Borax...
20 Mule Team All Natural Borax...
  • Add to laundry to help remove tough stains,...
  • Wipe on counters and appliances to remove grease...
  • Removes soap scum, hard water deposits, and dirt

What Can Borax Do For My Pool?

Not only is borax an inexpensive and extremely useful product to have around the house, but it’s also been shown to be a champ in the backyard as well. Who would have thought that adding some borax to your pool could be so beneficial?

Borax can:

  • Increase the pH of your pool water if things have gotten too acidic
  • Act as a buffer for your pH, protecting your sanitizer levels
  • Prevent algae and bacteria growth (because your sanitizer is happy)

The Backyard Benefits of Borax

Keeping your pool water chemistry in-check can sometimes be a tricky beast to master. Balancing pH, alkalinity, sanitizer levels, and minerals might seem like a feat only a chemist could achieve, but with borax, things just got easier.

Back in the day, pool owners would turn to sodium carbonate or bicarbonate, also known as soda ash and baking soda to increase the pH of their pool water when it got too acidic. Those products do work well as pH increasers, however, they have the nasty side effect of raising the total alkalinity of the water too.

Borax For Increasing pH

In the right amounts, borax will do a great job of increasing the pH of an unbalanced pool. Not only that, but it will do so without raising the total alkalinity in the process. Since borax is not a carbonate compound, its effects on the water’s alkalinity will be negligible.

Borax As a pH Buffer

In the constant battle with perfect pH balance, think of borax as your white knight. This handy little product will not only fight off the dragons of low pH but will keep the realm safe longer by building a fortress around your pH to keep it stable at all times and unaffected by unseen attacks and chemical changes.

The Staying Power of Borax

Unlike the other carbonates, borax actually stays in your pool water once it has dissolved. The chemical nature of baking soda and soda ash causes them to evaporate after they’ve dissolved and done their part.

Borax, on the other hand, won’t evaporate. It’s basically immortal. It will live forever in your water, working its chemical butt off, and saving you money in the long run.

Borax As an Algaecide

Okay, borax is not technically an algaecide and there are plenty of other products out there that will do the job better than borax. What is does do, however, is basically the same thing. Adding borax (at the proper amounts) to your pool stabilizes your pH levels, which allows your sanitizer to do its job right.

Pool water sanitizer can only work as long as the pH levels are right and the total alkalinity is where it needs to be. Letting your chlorine live its best life is the best protection against algae and other bacterial growth you can have.

20 Mule Team All Natural Borax...
20 Mule Team All Natural Borax...
  • Add to laundry to help remove tough stains,...
  • Wipe on counters and appliances to remove grease...
  • Removes soap scum, hard water deposits, and dirt

The Importance of pH & Total Alkalinity

Perfectly pH-balanced pool water is a complex and delicate dance. You’ve probably faced the struggle of how to maintain a steady, optimal pH without raising the total alkalinity. You add a pH increaser (like baking soda or soda ash) and while they do the trick, they also raise the alkalinity as an annoying side effect, causing you to have to add more chemicals to fix the problem.

The Perfect pH

Ideally, you want to keep the pH of your pool water between 7.2 and 7.6. Anything higher or lower than that will either corrode your equipment or negate the effectiveness of your sanitizer. 

A high pH (7.8 or more) will reduce the cleaning power of your chlorine, allowing for rampant bacterial growth. 

Having a pH level below 7.2 will not only reduce the cleaning ability of your sanitizer, but the acidity can also cause eye and skin irritation for swimmers. The longer the pH stays that low, you may notice a build-up of lime and some of the stone or concrete of your pool slowly start to dissolve.

Totally Awesome Total Alkalinity

Total alkalinity is a very important measurement in your pool chemistry and one you should be testing several times per week. The optimal levels for TA are between 80 and 120 ppm (parts per million).

Having alkaline substances in your pool water acts as a pH buffer to keep that delicate balance from being tossed about every time it rains or you have a pool party. And guess what alkaline substance is going to be your pool water’s new best friend? You guessed it: borax.

How to Use Borax in Your Pool

So if your pool water’s pH is too low and you need help, keep reading! But before you run to the store to buy a truckload of borax, there are a few things you need to figure out.

  1. First, find the capacity of your pool, your pool’s current total alkalinity, and the amount that your pH needs to be increased.
  2. Next, use a water-chemistry calculator to determine how much borax to add to your pool.
  3. Make sure you have the pool’s pump and filter running, then add the borax to the skimmer.
  4. Finally, wait at least 24 hours and take another water sample to retest.

If you’re using borax to raise the pH of your pool water, you can add borax all by itself. If, however, your pH is fine but you’re looking to add more alkalinity to buffer your pH, you may need to add borax with an acid to balance the pH.

This is where the one downside of borax rears its ugly head. On its own, borax has a pretty high pH; it’s actually about 9.5. 

If you’re adding large amounts of borax, you’ll run the risk of increasing your pH too much. Counteract this issue by adding muriatic acid (or another pH reducer) when introducing borax to the equation.

Find Balance With Borax

Are you feeling the zen balance yet? 

If not, chances are you need a dip in your pH-perfect, algae-free swimming pool to relax. Because keeping your pool water pH-balanced has never been easier with this unassuming household cleaner.

Categories: Pool Care, Pool Chemistry