Swimming Pool Alkalinity: Definition, Ranges, How to Raise and Lower

Total alkalinity is a measure of the total amount of alkaline materials dissolved in the water. Total alkalinity acts as a pH buffer, preventing the pH from decreasing. Total alkalinity indicates the water’s resistance to pH change and its ability to neutralize acid. It is also a measure of the soluble minerals present in the water. While a pH test tells you the relative acidity or alkalinity of the water, total alkalinity tells you the quantity of alkaline material in the water. Total alkalinity helps predict the amount of acidic material required to reach a desired pH.

What is the ideal Total Alkalinity level?

The ideal total alkalinity ranges from 80 to 140 parts per million (ppm), depending on the type of chlorine or regular sanitizer used. Both high and low total alkalinity cause problems that may require expensive remedies.

What are the effects of low Total Alkalinity in the pool?

The signs of low total alkalinity in the pool include unstable pH levels, a phenomenon often referred to as pH bounce or the “yo-yo” effect. Low total alkalinity also makes the water corrosive or aggressive, leading to the dissolution of plaster pool walls (plaster etching) and metal parts in circulation, filtration, and heating equipment. This increases the likelihood of metal stains appearing on the pool walls and bottom.

Low total alkalinity in a pool leads to a continuous decrease in the pH level. This instability results in significant fluctuations in the pH whenever chemicals are added to the water, a phenomenon known as pH bounce or the “yo-yo” effect. Additionally, low total alkalinity makes the water corrosive or aggressive. This leads to the dissolution of plaster pool walls, a process known as plaster etching, and the corrosion of metal parts in circulation, filtration, and heating equipment. As a result, metal stains appear on the pool walls and bottom.

How to increase Total Alkalinity in the pool?

To increase total alkalinity in the pool, sodium bicarbonate or soda ash is added. Sodium bicarbonate is used to increase total alkalinity without significantly altering the pH. Adding 1 pound of sodium bicarbonate to 10,000 gallons of water raises total alkalinity by about 7.1 ppm with only a slight change in pH. To raise both total alkalinity and pH, soda ash is used. Adding 1 pound of soda ash to 10,000 gallons of water increases the total alkalinity by 11.3 ppm and raises the pH from 0.35 to 0.71, depending on the starting pH and total alkalinity.

How to increase Total Alkalinity of the pool with sodium bicarbonate?

Increasing the total alkalinity (TA) of the pool with sodium bicarbonate involves adding 5 lbs of sodium bicarbonate to a pool with a volume between 15,000 to 30,000 gallons. The sodium bicarbonate must be weighed accurately and distributed evenly in the pool water with the pump on. After adding the sodium bicarbonate, wait for 1-3 hours for it to disperse and blend completely in the pool water.

The calculation of the required amount of sodium bicarbonate to increase total alkalinity (TA) in a pool involves a specific formula. For example, the initial total alkalinity is 100 parts per million (ppm). After adding sodium bicarbonate, the total alkalinity increases to 116 ppm, resulting in a change of 16 ppm. The volume of the pool in gallons is determined by using the formula. In this case, 71,400 (a constant representing the number of gallons that 1 pound of sodium bicarbonate will treat to increase total alkalinity by 1 ppm) is multiplied by the amount of sodium bicarbonate added, which is 5 lbs. This product is then divided by the change in total alkalinity (16 ppm) to yield the total volume of the pool in gallons.

Sodium bicarbonate, also known as baking soda, has a pH of 8.3. Sodium bicarbonate is used when is needed a raise in total alkalinity without significantly changing the pH. Adding 1 pound of sodium bicarbonate to 10,000 gallons of water increases total alkalinity by about 7.1 ppm.

To calculate the total amount of sodium bicarbonate needed to raise total alkalinity, three given values are multiplied. For example, if the first value is 2.24 oz (the amount of sodium bicarbonate needed to increase total alkalinity by 1 ppm), the second value is 1.5 (the volume factor for a 15,000-gallon pool), and the third value is 50 (the desired increase in total alkalinity), the calculation would be 2.24 oz. × 1.5 × 50 = 168.0 oz. This is then converted to pounds by dividing by 16 (oz in a lb), giving us 10.5 pounds. Therefore, 10.5 pounds of sodium bicarbonate is needed to raise the total alkalinity by 50 ppm in a 15,000-gallon pool.

How to increase Total Alkalinity of the pool with soda ash?

To increase the total alkalinity of the pool with soda ash, the soda ash is added directly to the pool. Soda ash, or sodium carbonate (Na2CO3), contributes to total alkalinity and has a pH of 11.7. Adding 1 pound of soda ash to 10,000 gallons of water increases the total alkalinity by 11.3 ppm. However, it is important to note that soda ash also raises the pH level of the water.

If the pH is slightly low (around 7.1 or 7.3) and the total alkalinity is near the target of 90 ppm, adding soda ash effectively adjusts both values to their appropriate levels. However, if the pH is low and the total alkalinity is appropriate, there is no chemical that solely raises the pH. Therefore, soda ash is best used when both total alkalinity and pH need to be increased.

For pools with a volume ranging from 15,000 to 30,000 gallons, it is necessary to add 5 lbs of sodium bicarbonate (baking soda) to the pool while the pump is running. Accurately weigh the bicarbonate and distribute it evenly in the pool water. Then, wait 1-3 hours for the bicarbonate to disperse and blend completely. After this, the pH and alkalinity of the water must be tested to see if further adjustments are needed.

Calculating the total amount of soda ash needed to raise total alkalinity involves considering the current and target total alkalinity levels, the volume of the water, and the effect of soda ash on total alkalinity. According to the given information, adding 1 pound of soda ash to 10,000 gallons of water increases the total alkalinity by 11.3 ppm. Therefore, it is necessary to calculate the difference between the target and current total alkalinity levels. Afterwards, determine the quantity of soda ash required to achieve this increase, based on the volume of your water.

For example, if the current total alkalinity is 60 ppm and the goal is to raise it to 90 ppm, this requires an increase of 30 ppm. If the water volume is 15,000 gallons, approximately 4.5 pounds of soda ash would need to be added, according to the formula: 30 ppm increase / 11.3 ppm per pound of soda ash * 1.5 volume factor for 15,000 gallons. These calculations are approximate and actual results vary. It is crucial to test the water after adding chemicals to ensure the desired levels have been achieved.

What are the effects of low Total Alkalinity in pool water?

Low total alkalinity in pool water causes the pH level to continually decrease, leading to unstable pH levels. This instability results in significant fluctuations in the pH whenever chemicals are added to the water, a phenomenon known as pH bounce or the “yo-yo” effect. Low total alkalinity also makes the water corrosive or aggressive, leading to the dissolution of plaster pool walls (plaster etching) and metal parts in circulation, filtration, and heating equipment. This contributes to the appearance of metal stains on pool walls and bottom.

Is low Total Alkalinity level in the pool water dangerous?

Yes, low total alkalinity level in pool water is dangerous.

Low total alkalinity in water causes the pH level to consistently decrease, leading to instability. This phenomenon is known as pH bounce or the “yo-yo” effect. Low total alkalinity also makes the water corrosive or aggressive, causing it to dissolve plaster pool walls (a process known as plaster etching) and metal parts in circulation, filtration, and heating equipment. The water then deposits these dissolved metals as stains on the pool walls. Therefore, maintaining the total alkalinity within the ideal range of 80 to 140 ppm is crucial for the health of the pool and its users.

What causes low Total Alkalinity in pool water?

Low Total Alkalinity in pool water is caused by the addition of acidic pool chemicals like muriatic acid. These chemicals lower the pH level of the water, which in turn decreases the total alkalinity. This is because total alkalinity measures the water’s ability to neutralize acid, acting as a buffer against pH decrease. Therefore, when acidic chemicals are added to the pool, they reduce the water’s alkalinity.

What are the signs of high Total Alkalinity in pool water?

Signs of high total alkalinity in pool water include a continually increasing pH level that is resistant to change. Even the addition of large amounts of acid affects the pH only slightly. When both the pH and alkalinity levels rise excessively, it leads to the precipitation of dissolved calcium and magnesium. This reaction promotes problems such as scale formation, metallic stains, cloudy water, short filter runs, eye and skin irritation, and poor chlorine efficiency.

How to lower pool Alkalinity?

To lower the total alkalinity of the pool water, the addition of specific amounts of dry acid or muriatic acid per 10,000 gallons of water is necessary. For instance, a pH between 7.6 – 7.8 is achieved by adding 12 oz. (about 2 cups) of dry acid or 10 fluid ounces of muriatic acid. Another method involves using a calculation-based approach where the desired alkalinity is subtracted from the current alkalinity to determine the desired change.

How to lower Total Alkalinity of the pool water with Muriatic Acid?

To lower total alkalinity of pool water with muriatic acid, specific formulas are used. These formulas involve dividing by 125,000 or 500,000 and then multiplying by the change in ppm. Once the required amount of muriatic acid is calculated, it needs to be added to the pool. For example, to lower the total alkalinity by 80 ppm in a 15,000-gallon pool, the addition of 2.4 gallons of muriatic acid is necessary. This method is part of a calculation-based approach for adjusting pool water alkalinity.

How to lower Total Alkalinity of the pool water with Dry Acid?

To lower total alkalinity of the pool water with dry acid, it is necessary to divide by 47,058 and multiply by the change in ppm. This calculation will determine the amount of dry acid needed to reduce the total alkalinity to the desired level. It is important to note that the amount of dry acid required varies depending on the initial total alkalinity and the desired reduction in ppm.

How to lower swimming pool water Total Alkalinity naturally?

The Nature’s Equilibrium Method is a natural way to lower the total alkalinity of pool water. This method involves lowering the total alkalinity of the pool water to the target of 90 ppm with muriatic acid. This will result in a low pH, usually less than 7.0 and possibly as low as 6.0. However, if the total alkalinity is maintained at 90 ppm and the pH is low, the pH will naturally return to approximately 7.5 over a span of several days, without any change in total alkalinity. Maintaining a very low pH in the pool for more than a few hours is not advisable. This condition increases the chance of metal corrosion, staining, plaster etching and causes the pool’s pH to continually rise, requiring the addition of acid, which in turn lowers total alkalinity. To correct a low pH, a base needs to be added, which affects total alkalinity.

What are the effects of high Total Alkalinity in pool water?

High total alkalinity in pool water causes the pH level to continually increase, making it difficult to alter the pH. Even the addition of large amounts of acid affects the pH only slightly. When both the levels of pH and alkalinity rise excessively, it leads to the precipitation of dissolved calcium and magnesium. This reaction causes problems such as scale formation, metallic stains, cloudy water, short filter runs, eye and skin irritation, and poor chlorine efficiency. High total alkalinity also causes the pool’s pH to continually rise, requiring the addition of acid, which lowers total alkalinity.

Is high Total Alkalinity in pool dangerous?

Yes, high total alkalinity in a pool is dangerous. High total alkalinity causes the pH level to continually increase, making it difficult to alter the pH. This leads to the precipitation of dissolved calcium and magnesium from the water, causing cloudy water and scale formation. Furthermore, high total alkalinity also causes serious problems that require expensive solutions. Therefore, it is important to maintain the total alkalinity within the ideal range of 80 to 140 ppm.

What are the effects of Alkalinity and pH on pool water quality?

Alkalinity and pH play crucial roles in maintaining pool water quality. Acidic pool chemicals like muriatic acid lower pH, while basic pool chemicals like soda ash and sodium bicarbonate raise pH. The total alkalinity determines the simplicity and rate of pH alterations. The ideal pH for pool water is 7.5. Low total alkalinity causes the pH level to consistently decrease, leading to instability and potentially causing the water to become corrosive. On the other hand, high total alkalinity results in a higher pH, which increases the chances of scale formation, metallic stains, cloudy water, and eye and skin irritation. Therefore, maintaining the right balance of pH and total alkalinity is essential for pool and spa care.

What is Alkalinity in chemistry?

In chemistry, alkalinity refers to the capacity of water to resist changes in pH, particularly a shift towards acidity. Essentially, it measures the water’s ability to neutralize acid. This is often referred to as the water’s buffering capacity. Total alkalinity, a specific measure of alkalinity, indicates the water’s resistance to a drop in pH. Total alkalinity acts as a pH buffer, maintaining the pH near a target level, typically around 7.5. The level of alkalinity in water varies based on the source of the water and the presence of alkaline materials.

What is pool Alkalinity balance?

Pool alkalinity balance refers to maintaining the total alkalinity of pool water within a specific range to act as a buffer against pH variations. The ideal range for total alkalinity in pool water is between 80 and 140 parts per million (ppm), depending on the type of sanitizer used. Total alkalinity maintains the pH near the target of 7.5, preventing the pH from decreasing. It indicates the water’s resistance to a decrease in pH, or in other words, the water’s ability to neutralize acid. Both low and high total alkalinity cause issues, so it is important to keep the alkalinity within the ideal range.

How to test swimming pool Total Alkalinity levels in water?

To test the total alkalinity (TA) levels in swimming pool water, it is necessary to collect water samples from the pool using clean plastic water bottles. These samples are then tested using a specific total alkalinity test method. In this method, each drop of titrant corresponds to 10 ppm of total alkalinity, ensuring accurate results. This testing is done using a Total Alkalinity Test Kit. The test involves adding the titrant to the water sample and counting the drops used. The titrant changes the water sample’s color, indicating the total alkalinity level. For example, if one drop of titrant equals 10 ppm of alkalinity, and it took 100 drops to change the color of the water sample, the total alkalinity of the water is 100 ppm.

What is the Alkalinity water scale?

The alkalinity water scale refers to the measurement of the total amount of alkaline substances in water. It is an indicator of water’s resistance to a decrease in pH, or in other words, its ability to neutralize acid. Total alkalinity acts as a pH buffer, maintaining the pH near the target of 7.5. Total alkalinity is measured in parts per million (ppm) and the ideal range is from 80 to 140 ppm. This scale is crucial in maintaining the balance of water conditions, as changes in total alkalinity are equivalent to changes in pH. For instance, a 20 ppm change in total alkalinity is equivalent to a 0.1 change in pH.

What is the importance Alkalinity for chlorinated water?

The importance of Alkalinity for chlorinated water lies in its role as a pH buffer, preventing the pH from decreasing. Total alkalinity indicates the water’s resistance to a reduction in pH and its ability to neutralize acid. This maintains the pH near the target of 7.5, which is crucial for the effectiveness of chlorine as a sanitizer. Both low and high total alkalinity cause issues, therefore it is important to keep the total alkalinity within the ideal range of 80 to 140 ppm. Low total alkalinity makes the water corrosive, causing it to dissolve plaster pool walls and metal parts in circulation, filtration, and heating equipment. On the other hand, when the total alkalinity of the pool is high, it leads to a continuous increase in the pool’s pH. To counteract this, acid must be added, which reduces the total alkalinity.

How to achieve Alkalinity balance in pool water?

A combination of air, muriatic acid, and sodium bicarbonate is used to achieve alkalinity balance in pool water. The ideal total alkalinity (TA) for pool water ranges between 80 and 140 ppm, with a target of 90 ppm. To adjust TA, sodium bicarbonate is used. If the total alkalinity is less than 140 ppm, hardness is less than 350 ppm, and pH is less than 7.4, adjustments are necessary. The pool pump must be turned on and kept running for 24 hours. After this, the pH and alkalinity of the water must be tested. If the alkalinity is too high, muriatic acid is added to lower it. If the pH is too low, aeration and turbulence are used to raise it without affecting the alkalinity. This process must be repeated until the desired pH and TA levels are achieved.

How does Total Alkalinity impact pool water balance?

Total alkalinity impacts pool water balance by measuring water’s ability to resist pH variations. Total alkalinity acts as a buffer, preventing significant fluctuations in pH that lead to water imbalance. These fluctuations influence the effectiveness of chlorine in killing bacteria and lead to issues such as corrosion, staining, scaling, or eye/skin irritation. The ideal total alkalinity level depends on the chlorine source and generally ranges between 80 to 120 ppm. High total alkalinity causes the pH level to continually increase, making it difficult to adjust the pH level, while low total alkalinity causes the pH level to continually decrease, leading to unstable pH levels.