Sodium Bicarbonate (Baking Soda) For Pools - What Does It Do?
Sodium bicarbonate, most commonly known by its household name ‘baking soda’, is an ingredient often found in your pantry that also has many uses in your swimming pool.
Baking soda can be used to adjust your pool’s pH or total alkalinity, which can help prevent corrosion and scaling, and is essential to maintaining the comfort of your swimmers.
This compound is also efficient at removing organic stains and algae from pool surfaces, when used to clear up occasionally cloudy pool water caused by rain or debris.
In this article, we will discuss how you can use baking soda to make adjustments to your pool’s chemistry as well as the most effective ways this product can be used for cleaning your pool.
Adjusting Your Pool’s pH Level
As you are likely already aware, your pool’s pH levels represent the degree of acidity or alkalinity in your pool’s water. An ideal pH reading for your pool should fall between 7.2-7.6, with 7.4 being best. If your pH is testing at levels of 7.2 or below, baking soda can be used to increase it.
Sodium bicarbonate has a natural pH level of 8.3, so adding it to your water in small amounts will slowly bring your pH levels up to the correct zone.
For pH levels of 7.2, we recommend adding 0.5kg of sodium bicarbonate to your pool, and letting this circulate for six hours or more before retesting your pH.
If your pH is much lower than 7.2, you may be better off using something like soda ash, which has a much greater impact on the pH than baking soda.
As we will discuss below, whether you use baking soda or soda ash, you will see a substantial lift in your alkalinity, which is closely related to the pH.
Adjusting Your Total Alkalinity
As we have discussed before, having low alkalinity in your pool can result in a variety of issues, ranging from wildly fluctuating and low pH to corrosion of pool pumps and filters. Thankfully, bicarbonate of soda can be used to resolve these issues.
First, test your pool’s total alkalinity levels using an appropriate test kit. Then, identify how low your alkalinity levels are. Ideal levels for total alkalinity fall between 80-120 parts per million (ppm), with 100ppm being the perfect amount.
In order to increase your pool’s total alkalinity using baking soda, you will need a reasonable amount of it. It is often more cost effective to buy sodium bicarbonate from a pool supply store because of the quantity needed.
Most pool supply shop alkalinity increasers are made up of 100% sodium bicarbonate, making them perfect for all of the uses we discuss in this article.
When you are ready to treat your pool, measure out an adequate dose for your volume of water. It takes around 150 grams of baking soda per 10,000 litres of pool water to raise total alkalinity by 10 ppm. For larger pools, a few kilograms are likely needed to make the appropriate adjustments.
Here is how to do the maths to find the correct dosage for your pool. First, divide the total amount of litres of your pool by 10,000. Then, multiply the answer you receive by 150. This result is the total number of grams you will need to raise your pool’s alkalinity by 10 ppm.
To create a greater increase in your pool’s alkalinity, you can further adjust the dosage from here. If you need an increase of 20 ppm, double the amount of grams from your last answer. This can also be tripled or quadrupled, for 30 or 40 ppm respectively.
If this sounds a bit complicated, just check out our pool baking soda calculator, which lets you enter your pool’s volume, current alkalinity level and desired alkalinity level. It will then let you know exactly how much baking soda you need to add.
When preparing a large treatment for your pool, we recommend breaking the amount of sodium bicarbonate you use up into smaller doses when adding it to your water. You should then retest your pool’s levels after six hours of circulation before adding the next dose to avoid adding more baking soda than necessary.
Cleaning Pool Surfaces
Baking soda has an abrasive texture, and also has many antibacterial properties associated with its salt content. This makes it a great choice for cleaning pool surfaces that may have developed organic stains, either from algae or from an accumulation of organic matter such as leaves.
Applying a paste of baking soda and water to stained equipment or areas on your pool’s lining can act as an effective scrubbing agent. Due to its fine particles, it works great as an extra layer of treatment when removing stubborn types of algae, such as black spot, and is also extremely effective on pool linings with a porous texture, such as with pebblecrete finishes.
Using a sodium bicarbonate and water paste and a stiff, plastic bristle brush to scrub affected areas is effective in removing stains. Baking soda can also be left to settle out in still water on organic stains or algae along the bottom of your pool and then be vacuumed up after a few hours to assist in your cleaning process.
If you already have a pH or total alkalinity level that runs high, take extra care when using baking soda for these purposes to avoid creating pool water that is too high in alkalinity. After using sodium bicarbonate for cleaning, always test your pool’s total alkalinity and pH to make sure the levels have not risen outside of the acceptable range.
Clearing Cloudy Pool Water
Baking soda is also very effective at clearing cloudy pool water, which often occurs to many pool owners after a rainstorm. Rainwater entering your pool can disrupt the pH and total alkalinity levels of your water, causing it to become cloudy.
When you notice cloudy pool water, it is important to test your pool’s pH and total alkalinity levels and make adjustments as needed.
Cloudy pool water is usually caused by low pH or alkalinity, so using sodium bicarbonate to increase these levels by following the directions provided in the sections above will effectively clear up your pool.
For pool owners with chronically cloudy water, or those who may live in a particularly rainy area, sodium bicarbonate can also be used as a preventative agent. Certain baking-soda based tablets are available that slowly dissolve in your pool’s skimmer basket and work to combat the causes of cloudy water as they appear.
Baking soda, or sodium bicarbonate, is a common household product often found in your pantry that can have a wide variety of uses for your pool.
Although much more product might be needed to treat your pool than you may have in your cupboard, this product still makes a cost-effective and non-toxic option when used for cleaning or to make adjustments to your pool’s chemistry.
Do you have any questions about the uses of baking soda for your pool? Or, do you need help calculating the correct dose of baking soda to raise your pool’s total alkalinity? Leave us a comment down below, we’d love to help!
A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.