How To Use Baking Soda To Raise Alkalinity In A Pool

The alkalinity level of a pool is important to keep the water healthy and clean. Too low an alkalinity level could increase the pH levels in the water and make it unsafe to swim in. Fortunately, homemade baking soda is the perfect remedy when it comes to a pool with a low alkalinity level. By mixing the right amount, you can enjoy the pool on those hot summer days.

Equipment you will need

Measuring tape
Titration evaluation kit
Sodium Bicarbonate
Measuring cup

Measure Alkalinity Levels

Get a Titration evaluation kit. Titration Assessment Kits are a thorough measurement system for assessing the alkalinity level of a swimming pool. These can be purchased at a pool specialty store or online. You can also use strips to measure alkalinity, although these do not have an accurate reading system.

Take a pool water sample at the level of the depth of your elbow. Submerge the tube that comes with the kit, into the water. Removing the water from this depth level ensures that the water has not been disturbed by anything in the air or sunlight. You will only need 0.85 oz (25 ml) to complete the evaluation. Remove any excess water in the tube.

Add 2 drops of sodium thiosulfate. Squeeze the tube gently so you don’t use too many drops. An incorrect amount of sodium thiosulfate will alter the results. Make sure to swirl the mixture in a spiral so that the water and chemical are completely mixed.

Pour in 5 drops of the alkalinity indicator and shake the tube in a spiral fashion. You will notice that the water changes color, from a light shade to a green color. Keep shaking the tube until the color is consistent throughout the tube.

Add the sulfuric acid reagent; 1 drop at a time until the liquid turns red. After adding each drop, mix the water. Count the number of drops you add to the water. Once the solution has turned red, stop adding the sulfuric acid. Wear gloves while handling sulfuric acid, in case you spill it.

Multiply the number of drops by 10. This will give you the parts per million (ppm) value of the alkalinity level in the pool. A pool should be between 80 and 100 ppm. Anything below this could affect the pH of the pool, while a higher value could cause scale formation. If the alkalinity level exceeds 100 ppm, do not add baking soda to the water. Instead, add Muriatic acid or sodium Bisulfate.

Measure The Volume Of The Pool

Measure the length and width of the pool to determine the surface area. Use a tape measure to determine the length and width of the pool, in case you don’t know the dimensions. Multiply the 2 numbers to determine the total surface area. This procedure is the simplest when it comes to a rectangular pool.

For a circular pool, measure the diameter of the pool and divide by 2 to find the radius. Square the radius and multiply the number by pi (π) (3.14).

If you have a triangular pool, multiply the length of the base, and the length between the base and the furthest point from the triangle. Divide the result by 2 to find the surface area.

If you have an irregularly shaped pool, you will have to find the average value of each measurement. Measure the shortest and longest lengths and add them together. Divide the number by 2 to find the average length. Repeat the process to find the average width.

Calculate the average depth of the shallow end and the deepest end. Unfold the tape measure to the bottom of the water at both ends of the pool. Once you have found the shallowest and deepest points, add the depths together and divide by 2 to determine the average value of the pool depth. If the pool is the same depth throughout the pool, you will not need to calculate the average value of the depth.

Multiply the surface area value and the depth value to find the volume. Once you have these two figures, multiply them together to find the volume of the pool. This will be found in either cubic feet or cubic meters, depending on the metric system you use.

Multiply the volume by 7.5 for cubic feet, or by 1000 for cubic meters. There are 7.5 US gallons in 1 cubic foot of water, but there are 1000 liters (260 US gallons) in one cubic meter of water. Multiply the volume according to the metric system you use to find the amount of water in the pool.

Add The Baking Soda

Add 1.25 lb (570 g) of baking soda for every 10,000 US gallons (38,000 L) of water. This will increase the alkalinity level in the water by 10 ppm. Adjust the values ​​to determine how much baking soda you will need to add based on the volume of the pool.

For example, if you want to go from 60 ppm to 80 ppm in a pool with a volume of 38,000 L (10,000 US gallons), you would add 1100 g (2.5 pounds) of baking soda.

Use only 2 pounds (900 g) of baking soda per day. Adding too much baking soda at one time could increase the pH level of the water. Let the baking soda sit and mix with the water before adding more.
If you need to increase the alkalinity level even more, wait until the next day to add more baking soda.

Pour the baking soda into the deepest end of the pool. Use a circular motion as you pour in the baking soda. It may cause cloudiness of the water at first. The baking soda will sink to the bottom of the pool and settle before it begins to mix. To avoid clouding of the water, pour the baking soda directly into the pool skimmer.

Retest the water after 10 hours and make other adjustments, if necessary. The pool water needs to be pumped and circulated for a full cycle before you test it again. Check the alkalinity level using the evaluation kit.

Let the pool go through a full pump cycle, which takes about 10 hours, before swimming. If the alkalinity levels are still outside the proper range after the first sodium bicarbonate treatment, add more bicarbonate to reach the desired ppm level.

Useful Tip
Check your pool’s pH and alkalinity levels weekly to determine if adjustments are required.