Baking soda or sodium bicarbonate is very useful to have around the home particularly in the kitchen. Baking soda can be used in baking of course and also in the fridge as a deodorizer. But did you know that baking soda can have positive uses in your salt water pool, too?
Baking soda is used in commercial pool products to raise alkalinity and prevent corrosion albeit at a higher price than standard baking soda. Baking soda can also be used in a salt water pool to help produce clear water and for spot cleaning of algae as a complement to chlorine effectiveness.
Large containers of commercial alkalinity-raising products weighing up to 16 lbs typically retail for about $1.25 per pound whereas large 13 lbs – 15 lbs bags of baking soda cost around $0.53 per pound.
Let’s take a closer look at using commercial alkalinity increasing products and baking soda in your pool to keep water levels in check.
Alkalinity increasing product vs baking soda
Expect to pay $20 for a 16 lbs bucket of commercial alkalinity increaser whereas you can find a 15 lbs bag of Arm & Hammer baking soda for $8. So the package sizes are slightly different but you’re paying $1.25 per pound of commercial alkalinity increaser and $0.53 per pound for the baking soda.
What’s the difference between the two?
A commercial bucket of alkalinity increaser’s ingredient list typically states sodium hydrogen bicarcarbonate as its main ingredient which is the International Union of Pure and Applied Chemistry (IUPAC) name for sodium bicarbonate which is also known as…baking soda.
So for the most part an alkalinity increaser is just sodium bicarbonate possibly with an extra ingredient or two either for marketing purposes or for an actual benefit. I checked the safety PDF safety data sheet for one particular alkalinity increaser and it referred to a “Trade Secret” in the section that specified product composition and ingredients. But the main ingredient is still baking soda.
Having said that, here’s a comparison as to how much alkalinity increaser you will typically need to use compared to baking soda to increase alkalinity by 10 ppm for every 10,000 gallons of water.
Using alkalinity increaser vs baking soda per 10,000 gallons of pool water
| To raise total alkalinity: | Alkalinity increaser product (add per 10,000 gallons) | Baking soda (add per 10,000 gallons) |
| 30 ppm | 4 lbs | 4.5 lbs |
| 40 ppm | 6 lbs | 6 lbs |
| 50 ppm | 7 lbs | 7.5 lbs |
| 60 ppm | 9 lbs | 9 lbs |
| 80 ppm | 12 lbs | 12 lbs |
| 100 ppm | 15 lbs | 15 lbs |
So to raise alkalinity by 10 parts per million (ppm), you would need 4 lbs of alkalinity increaser or 4.5 lbs of baking soda. You can see by the chart that other than rounding up for 30 ppm and 60 ppm examples, the ratio of alkalinity increaser vs baking soda used is the same.
The difference?
Regular baking soda is much cheaper to buy.
In over 10 years of salt water pool ownership, my original pool company never told me once about using baking soda for any reason. It was never suggested and instead I was pointed in the direction of their higher priced alkalinity increaser instead in the rare cases it was needed.
Risks of using baking soda in your salt water pool
The ideal pH in a salt water pool is in the range of 7.0 – 7.6 which is in the neutral area. Baking soda has a pH of 8.3 which means it trends towards alkaline. While baking soda has benefits to your salt water pool when required, there are a few considerations to think about.
See the chart below for some comparisons between things that are acidic on one end of the scale and alkaline on the other.
While adding baking soda to your pool will increase its alkalinity to neutralize certain things that are more acidic that can enter your pool such as rain, the only thing that you can add to your pool that will raise the alkalinity is baking soda. So you have to be careful not to add too much and throw the pH out of whack.
Adding too much baking soda to your pool can raise the pH to the alkaline level which can have negative implications: A high pH means potential side effects like calcium and scale deposits in the pool, cloudy water, irritated skin and a loss of effectiveness of chlorine.
The only time you would want to add baking soda to your pool is when the pH level is measuring less than 7.2. Use a rule of thumb of adding 1.5 pounds of baking soda to increase the alkalinity by 10 ppm for every 10,000 gallons of pool water.
So if your pool needed to be raised by 20 ppm and you had a 20,000 gallon pool, you’d double the formula’s ppm and gallon rating to get the following:
1.5 lbs X 2 X 2 = add 6 pounds of baking soda.
Sprinkle the baking soda over wide areas of the pool surface with the pump running rather than dumping it in one spot.
Note: You might find slightly different calculations that produce a differing amount when calculating baking soda needs. It’s best to put less baking soda in your pool and wait 24 hours with the pump running and then test again to see what the result is. If your pH is still below 7.2 and the alkalinity is below 110 ppm, you can add more baking soda to bring the pH up closer to 7.4.
Soda ash vs baking soda in your salt water pool
Soda ash or sodium carbonate has a pH of 11.4 making it much higher than the 8.3 pH of baking soda. Soda ash can be used in place of baking soda when you want to raise pH without touching your alkalinity. Soda ash should be added and mixed in a bucket of water and then slowly poured along the sides of the pool.
To raise the pH in your pool by 0.1 ppm, add 7.1 ounces of soda ash for every 10,000 gallons in your pool.
So a 20,000 gallon pool that requires the pH raised from 7.1 ppm to 7.5 ppm (0.4 ppm increase) would need 5.68 ounces of soda ash: 7.1 ounces X 2 X 4 where the 2 represents doubling the formula for the 20,000 gallons and 4 represents the 0.4 ppm increase in ppm.
One consideration of adding baking soda to a pool is when a large amount is required to raise the pH. Adding large amounts of baking soda to your salt water pool can throw alkalinity out of whack if you’re trying to only increase pH. So while you fix one problem (low pH) you can create another one (high alkalinity).
A solution is to instead use soda ash which is also known as sodium carbonate. You use less soda ash than you would baking soda as you can see from the ratio above.
NOTE: Do not add more than 1 pound of soda ash per 10,000 gallons of water at a time as it may cause the pool to become cloudy. Don’t allow swimmers in the pool while you’re putting soda ash in and allow the mixture to dissipate for an hour before recommencing swimming.
Chlorine effectiveness based on your salt water pool pH level
Balancing your pool water involves several key metrics including salt, chlorine, pH, alkalinity, stabilizer and water hardness. pH is particularly understood to be an important aspect of water balancing and pool water health.
The human tear has a pH of 7.5 so the closer you can get your pool to this level the better as it’s right within the proper pH range. Proper pH also helps to ensure that your chlorine is effective and also ensures the water doesn’t damage pool equipment.
When pH drops below 7.2 you’re likely to experience chlorine loss, metal equipment damage, staining of plastic stairs, pool vinyl wrinkling and irritation of your eyes and skin while swimming.
When pH goes higher than 7.8 you’re likely to experience filters getting clogged, reduced water circulation, heater problems, reduced effectiveness of chlorine and irritation of your eyes and skin while swimming.
pH and effective free chlorine table for salt water pools
How important is pH to the effectiveness of chlorine? Here’s a table that shows chlorine’s effectiveness at various pH levels.
| pH | Effective Free Chlorine |
| 6.0 | 97% |
| 7.0 | 75% |
| 7.2 | 63% |
| 7.5 | 49% IDEAL RANGE HERE |
| 7.6 | 39% |
| 7.8 | 28% |
| 8.0 | 3% |
So while chlorine would be 97% effective if your pool pH was 6.0, this level is too low because you’d experience the negative aspects of low pH as listed above.
Instead, a good pH level of 7.5 means your chlorine is about 49% effective which is the ideal pH range of where you’d like to be.
Using baking soda to deal with spot algae reduction
Green algae is something the average salt water pool owner will experience from time to time. It’s usually a sign of low chlorine so get your water checked by your pool company and get chlorine within the acceptable 1 ppm – 3 ppm range quickly.
If the algae breakout is confined to a small area you can deal with it specifically. If the breakout is larger and significant, get a bottle of algaecide and add that to the pool with the pump running. The next day, you can sprinkle baking soda in the areas of the pool with algae and scrub them with a brush to remove the algae.
For more direct spot cleaning, apply baking soda to a cloth or other moist cleaning device and rub it on the affected areas to remove the algae.
Summary
One of the benefits of a salt water pool is using less chemicals (ie. less chlorine) than with a regular pool. But salt water pools do utilize other chemicals similar to a chlorinated pool for algae, metals, pH and other aspects of pool chemistry. So it’s nice to know that you can use something natural like baking soda to achieve benefits without going down the route of dumping more chemicals in the water.
Can you use baking soda in your salt water pool? Yes but with several provisos and cautions.
Baking soda is good to use when you want to raise the alkalinity of a pool but isn’t as effective to raise the pH. It takes a great deal of baking soda to raise pH so you’re less likely to throw pH out of whack when you use it to raise alkalinity.
Soda ash is better than baking soda when you want to raise the pH level without impacting the overall alkalinity of the pool to a great degree.
Want to learn more about using baking soda in your salt water pool? Check out my article called Can You Use Baking Soda In Salt Water Pool Systems to read more details about how much it costs and the benefits.
