Does Baking Soda Increase Calcium Hardness in a Pool?

With a great pool comes great responsibility. Maintaining a great pool requires constant cleaning, diligent monitoring of chlorine, pH, alkaline, and calcium hardness levels, and the added burden of repairing the temperamental equipment that keeps things flowing smoothly. Calcium hardness is a crucial component of safe, comfortable, and attractive pool water, and luckily, it’s easy to increase the hardness of your pool water with baking soda.

Baking soda increases calcium hardness in a pool. Using baking soda to raise calcium hardness is an inexpensive and effective way to prevent hardness-related issues like grout and plaster damage, corrosion, and pitting. 

So, let’s discuss why you need to monitor the calcium hardness in your pool water. I’ll teach you how to test and balance the hardness of your pool water with baking soda so that you can keep your pool in pristine condition. I’ll also tell you more about the other benefits of using baking soda to maintain your pool, so let’s get into it. 

baking soda increases calcium hardness

What Is Calcium Hardness?

Calcium hardness refers to the concentration of calcium ions in water. Measured in parts per million (often abbreviated as ppm), your ideal calcium hardness level depends on the type of swimming pool you own.

Here are some of the best calcium hardness labels for different pool types:

  • The recommended calcium hardness level for plaster or concrete pools is 200 to 275 ppm.
  • The recommended calcium hardness level for fiberglass or vinyl pools is 175 to 225 ppm.

How To Measure Calcium Hardness in Swimming Pool Water

The two most popular methods for testing calcium hardness in pool water are Calcium Hardness Test Strips and Calcium Hardness Test Kits. Test strips are the least expensive and easiest to use, and they are just small paper strips that will change color, indicating your calcium hardness levels. 

However, investing in a test kit will give you more accurate results. Test kits usually come with a vial and some water testing solution. When you add the testing liquid to your pool water in the vial, it will change color, indicating the hardness levels. 

Using Baking Soda To Increase Calcium Hardness

Now that you know the calcium hardness level of your pool water, what are you going to do about it? If the level is below the recommended levels mentioned above, you will want to bring it up as soon as possible. You can easily do this with the addition of baking soda.

How Much Baking Soda Should I Add?

The odds are good that the box of baking soda sitting in the back of your fridge will not do the trick. 

You should add 1.5 lbs (0.68 kg) of baking soda to raise the alkalinity of 10,000 gallons (37.85 kl) of water by about ten ppm. So, if your pool water’s calcium hardness is 80 ppm, it will take 12 pounds (5.44 kg) of baking soda to bring 10,000 gallons of that water up to 240 ppm. 

Since many average-sized pools contain double the volume of water in our example, you could be looking at using 24 pounds (10.89 kg) of baking soda! On the bright side, my original test number of 80 ppm is rather pessimistic. 

Unless the water in your community is exceptionally soft, your calcium hardness test numbers should be a bit higher than my example, which means you’ll require a bit less soda. The volume of water in your pool and your calcium hardness test number will determine how much you’ll need. So, there is some math involved.

I strongly recommend erring on the side of caution when adding baking soda to your pool water. Start with about one-half to three-quarters of the amount you calculated you’ll need. If your testing results are still low after adding your initial amount of baking soda, it is easy to add more. 

If you add too much the first time, balancing things out by adding an acid or draining a portion of the water and replacing it with fresh water can get messy. A light hand and a little patience can help avoid unpleasant headaches.

How To Add Baking Soda to Swimming Pool Water

Please do not attempt to add baking soda (or any other powdered chemical) to your pool on a windy day. The goal is to integrate the soda into your pool water, not scatter it throughout the neighborhood.

For best results, spread the soda in wide arcs across the pool’s surface and turn on your pool’s circulation system. Wait at least six hours before retesting the water’s calcium hardness and add more soda if needed.

While it is perfectly safe to swim in the pool immediately after adding baking soda to the water, I recommend waiting the six-hour waiting period after your initial application for best dispersal results.

Additional Benefits of Adding Baking Soda to Pool Water

  • Many pool owners add too much acid to pool water to sanitize the water. The addition of so much acid creates a low alkaline condition which can cause burning eyes and irritated skin. The addition of the proper amount of baking soda can help resolve this issue.
  • Aggressive algae treatments can undermine calcium hardness. Baking soda is an inexpensive and effective way to help bring calcium hardness back to a proper level after algae removal.
  • Contrary to popular belief, the addition of baking soda does not soften your pool water. Instead, it hardens your water. That said, most people report that it does make the water feel smoother and more comfortable on the skin. We can all agree that comfortable water is excellent for your swimming pool.
baking soda can sanitize your pool

Final Thoughts

Although there are days when owning a pool can feel like a lot of work, most pool owners have experienced days when all the work and all the worry seem to fade into the background. Golden moments sharing their special place with family and friends often create warm memories they will share for years to come. 

With all the expensive and complicated pool maintenance options available in the marketplace, it can also be a great comfort knowing simple old baking soda can be a helpful tool in keeping your special place truly special in the years to come.