Baking soda has many uses around the house, and many people are surprised that it can also be used in pool care. But what does baking soda do to a pool?
Baking soda is actually sodium bicarbonate, which is an alkaline, so adding it to a pool that is too acidic will raise the pH and also the total alkalinity. This will allow the chlorine in the pool to work more effectively to keep the pool water clean and clear.
Many people head to their local pool store and buy relatively expensive “pH or alkalinity increaser” believing to to be some kind of specialist product. However, most tubs of this simply contain sodium bicarbonate – simple baking soda. So if you can just go and buy some baking soda in bulk and save money.
In this article we will go into some of the benefits and drawbacks of using baking soda in a pool as well as the best time to add for maximum benefit. Find out all this information and more below.
What does baking soda actually do in a pool?
Baking soda is generally used to neutralize a pool if it is too acidic. This is because baking soda is an alkaline, normally with a pH or around 8-8.3. So it is not strongly alkaline – just slightly above neutral.
The benefits of baking soda to a pool are numerous and include:
- Helps to make chlorine more effective at sanitizing the pool’s water
- It can make the pool’s water feel softer
- If a pool’s water is cloudy it can help to bring it back to being clear and sparkling
- It can help with algae treatment
- Used to reduce the acidity, it reduces the risk of corrosion to things such as chrome pool ladders and other pool equipment which can take place when the water is more acidic
How to use baking soda in a pool
Below is the method I use when I want to add baking soda to my pool to raise the pH and total alkalinity levels.
Total time depends on amount to be added 1 hour
Test the pool water
Test you pool water to find out the pH and total alkalinity levels using test strips of whichever method you prefer. If the pH is between 7.2 and 7.8 and the total alkalinity is above 80ppm then you don’t need to add any baking soda.
Work out how much baking soda to use
If your total alkalinity is below 80ppm then you need to decide how much baking soda to add to bring the reading up to the level required. Refer to the table below (remembering to adjust for the volume of your pool). So as an example, if your pool was 20,000 gallons and the reading was 60ppm then you would need to add 12lbs of baking soda (20,000/10,000 x 6lbs).
Add baking soda (slowly)
Adding baking soda should be done in stages over a few days if you need to add a substantial amount. Anything over 3lbs should not be added at once otherwise this can cause problems.
With your pool pump running, you should add the baking soda by one of three methods:
1. Fill a bucket with water and add about half a pound of baking soda. Mix this around until at least most of it is dissolved and then walk around the edge of the pool slowly pouring it as you go. Then repeat as necessary. This is by favored method).
2. Using a scoop, walk around the pool and scatter the baking soda across the surface of the pool as you go.
3. Slowly pour the baking soda into a skimmer so that it is then gets pushed out of the pool returns and mixes with the water (my least favored method).
Run pool pump
You need to ensure that the baking soda gets thoroughly mixed around your pool and the best way to do that is to run your pool pump until you are happy with your new test results. If adding quite a bit of baking soda I would normally add it in the evening and run the pool pump overnight.
Test water again and repeat if necessary
After you have given the baking soda sufficient time to mix thoroughly around the pool (at least an hour but preferably longer) then retest the water again. If the pH and total alkalinity levels are still too low then repeat the above.
How much baking soda to add to a pool
|Alkalinity Reading||Baking soda to add per 10,000 gallons|
|100ppm or above||Do not add any baking soda|
The table above will give you an idea of how much baking soda to use to raise the alkalinity in your pool. You will need to know the volume of water in your pool – if you are not sure then it can be quite easy to calculate. It is something you will need to know for many things when maintaining your pool so it is worth calculating now:
For an oblong pool with a constant depth it is easy. Just multiply the width by the length and then by the depth (in feet) to give the cubic feet of water. You then multiply this figure by 7.5 to give the volume in gallons. If your pool has a shallow and a deep end then use an average depth (perhaps mid-way between the two depths.
Round pools, oval pools, kidney pools and other shapes make it more complicated. Rather than turn this into a mathematics post, I suggest you look on your cell phone for an app which will help you calculate the volume of a pool. There are plenty there to choose from.
You should avoid adding too much baking soda to the water of your swimming pool all at once, as this will probably result in cloudy water which will take a while to clear up.
How often should you put baking soda in your pool?
There is no hard and fast rule regarding how frequently you should use baking soda in your pool. Just use it as necessary to maintain the correct pH and alkalinity levels after testing your pool’s water..
You will probably need to use it more frequently during peak swimming season when your pool gets used most often and less so during the off-season.
Does baking soda raise pH?
Baking soda will raise the pH in a pool, assuming that the current pH of the water is less than 8. However, it will also increase the total alkalinity so you need to check these levels before you use it to ensure that the total alkalinity is also low.
To raise the pH without increasing total alkalinity you would normally use soda ash (sodium carbonate) instead of baking soda.
Pool Maintenance Course
When I first bought my house with a swimming pool I knew nothing about how to clean and maintain it. I was recommended Swim University’s Pool Care Handbook and video course so I bought it and have never regretted it.
It was probably the best money I spent that year as I have saved thousands by doing it myself.
Best time of day to add baking soda to a pool
Frankly it doesn’t make too much difference what time of day (or night) you add baking soda to your pool. It will work just as easily if added in the morning as it will in the evening.
The only thing I would say is to add it when the pool pump will be running for some hours afterwards to ensure that the baking soda is thoroughly mixed throughout the pool.
What if you add too much baking soda to pool
If your pool water is hard then adding too much baking soda can cause a build up of calcium which can lead to cloudy water as well as scaling around the edge of the pool and on other pool equipment.
Since the pH of baking soda is around 8.3 then it cannot increase the alkalinity level in the pool above this, not matter how much you put in. As an aside, soda sh, the other chemical used to increase the pH in a pool, has a much higher pH of around 11.5. So adding too much of this can significantly raise the pH.
Is baking soda safe to use in pools?
Since baking soda is used in food and even in toothpaste it can be generally considered to be safe. When adding it to a pool on a windy day then just make sure it doesn’t blow in for face or eyes.
Can you use baking soda to kill algae?
Baking soda will not actually kill algae. Having said hat, using baking soda to maintain the correct pH in the pool will help to prevent algae growth in the first place.
Can baking soda lower pH in a pool?
Although it isn’t a method that would be recommended (as there are better ways) if you had very high pH then, as the pH of baking soda is around 8, adding it would help reduce the pH down towards 8.
Can I use baking soda if my pool is cloudy?
Yes you can use baking soda if your pool is cloudy as part of the solution to clearing the water. Getting the correct balance between pH and alkalinity before adding chlorine will help speed up recovery from cloudy water.
Can you swim after adding baking soda to a pool?
Since baking soda is not a harmful chemical it would be safe to swim straight away after adding it to your pool, provided the other readings in your pool are ok.