What Does Baking Soda do for a Pool?

There is a lot of misunderstanding and false information about baking soda and swimming pools. Some say baking soda can clear cloudy water, others think it can clear up algae, neither of which is true. What does baking soda actually do in swimming pool water?

Baking soda, which is also known as bicarbonate of soda or sodium bicarbonate, can be used to raise the alkalinity of a pool without raising the pH. Unlike soda ash, which is also used to raise the alkalinity of the pool water along with raising the pH.

How to Raise the Alkalinity of Pool Water Using Baking Soda

It is important to keep the water of your pool in balance, and this includes keeping you alkaline balanced too. To do this, I recommend that you test the alkalinity of your water every week using Aquachek 7 test strips. Your alkaline levels should be between 80 and 120ppm. If your alkaline is too low, (but the pH is fine) you need to raise your alkaline, here’s how.

  • Head on over to your nearest swimming pool supply store and buy 5lbs of baking soda (also known as sodium bicarbonate) for every 10,000 gallons of pool water. Make sure you get baking soda and NOT soda ash!
  • Test the water before you add anything to the pool. Write down the result.
  • Open the skimmer basket and make sure it is clean.
  • Turn on the pump, and leave it running. Now add 1lb of baking soda for every 10,000 gallons of pool water into the skimmer basket.
  • Wait for 3 hours and test the alkalinity of the pool water again.
  • If the alkalinity it still too low, then repeat the process until your have reached the desired alkalinity levels.

There you have it, that is literally the only thing you’ll need baking soda in your pool for. Let’s talk about some of the rumours out there about adding baking soda to pool water.

Misconceptions About the Use of Baking Soda in Pool Water

There are a lot of other misconceptions about baking soda, here are some of the issues that baking soda is said to fix, and how to ACTUALLY fix them.

Will Baking Soda Clear Up a Cloudy Pool?

No, baking soda or bicarbonate of soda will not clear up cloudy pool water.

Cloudy pool water usually means one of the following problems:

  • Filter sand is dirty. You need to make sure that the sand in your filter is not depleted or worn out. Try to deep clean your filter by backwashing your filter for 3 minutes, then run it on filter mode for 15 seconds, then backwash again and repeat 3 times.
  • Filter sand is low, calcified, or worn out. In all three of these scenarios, you will need to change the sand in your filter. The sand in your filter needs to be changed every three to five years.
  • Your water is hard – High calcium hardness. Calcium Hardness is the amount of dissolved calcium and magnesium that is in the water.  Water with low calcium hardness is referred to as soft water, and water with high calcium hardness is referred to as hard water.

    If you have hard water, there is very little you can do chemically to lower it, other than replacing it. You should be replacing the water in your pool every five to 7 years.

    Pool flocculant can help to lower calcium hardness by binding SOME of the calcium and causing it the clump up and collect at the bottom of the pool, which can then be vacuumed up. This will make very little difference and is only kicking the can down the road as you will need to change your water soon anyways.
  • pH out of balance. The ideal pH level of pool water is between 7.2 and 7.8.

    To lower your pH, you need to add muriatic acid to you water. Add about 1lb of muriatic acid per 10,000 gallons then wait a few hours to test your water again. Repeat this process until you have reached the desired pH level.

    To raise your pH level, you need to add soda ash. Add 1lb of soda ash for every 10,000 gallons of water to your pool water while the pump is running. Then wait a few hours and test the water again. If the pH is still too low, repeat the process until the desired level is reached.

  • Natural dirt and debris. To fix this, set your pool pump to run full time, making sure to backwash it properly every few hours so that the sand in the filter stays clean.
  • Too much or too little chlorine. Your pools’ chlorine levels should always be between 1 and 3 ppm (parts per million). If it is too high, simply leave it for a few days, the chlorine will eventually clear out. Make sure your add only enough chlorine to maintain the correct levels in the future.

    If your chlorine levels are too low, you will need to bump up the dosage accordingly. Play around with doses until you consistently test the water to be between 1.0 and 3.0 ppm.

Will Baking Soda Kill Algae?

No, baking soda will not kill the algae in your pool.

Severe algae is best removed by triple shocking the pool. Here is a summary of a pool shocking process. Read my article “How Do You Clear a Green Pool Overnight?” for a more detailed description of this.

  1. Add 3lbs of chlorine for every 10,000 gallons of water, and leave it to kill the algae. Do not use algaecide with chlorine, the chlorine will simple deactivate the algaecide and you will just be wasting your money.
  2. Brush the pool vigorously immediately after shocking it. This helps to mix in the water with the chlorine. Now let it sit for a few hours and brush it again and leave it overnight with the pool cleaner running if you have one.
  3. The next day your pool should be looking a lot clearer, however, there will be a ton of dead algae on the surface of your pool. Connect up your vacuum, and start sucking all that junk out. Have your pump set to waste while doing this so that the dead algae doesn’t get stuck in your filter, or get pumped back into your pool.
  4. Backwash your pool filter 3 times before connecting up your pool cleaner. You can now set your pump back to filter and return to your normal pool cleaning schedule.


There you have it. Baking soda does not clear cloudy pool water. Baking soda also will not kill algae at all.

The only reason you will ever need to add baking soda to your pool water, it to raise the alkalinity of the water.

What is the difference between baking soda (bicarbonate of soda) and soda ash?

Baking soda is used to raise the alkalinity of the pool without raising the pH, while soda ash raises the pool’s alkalinity and pH together.

Leave a Reply

Your email address will not be published. Required fields are marked *