Muriatic Acid is another name for hydrochloric acid. Hydrochloric acid (HCl) is a compound that is formed when hypochlorous acid (HOCl) is used in an oxidation reaction, or after it has finished killing organisms, or when chlorine is destroyed by sunlight. The amount of acid produced is almost equal to the amount of hydroxide produced, so the net difference to pH is zero.
Contents
What is the role of hydrochloric acid in the pool?
Hydrochloric acid, also known as muriatic acid, is used in pools to lower the pH and total alkalinity when they exceed the recommended levels. It can also be produced when hypochlorous acid, formed from chlorine, is used up or destroyed by sunlight.
How to increase Muriatic Acid in the pool?
To increase the amount of Muriatic Acid in the pool, you need to add the acid directly to the pool water. The exact amount depends on the current pH and alkalinity levels of the pool. For example, if the pH is between 8.0 – 8.4, you need to add 18 fluid ounces of muriatic acid per 10,000 gallons of water. Always add the acid near a return line to ensure good mixing and keep the pump running for 24 hours after adding the acid.
What are the safety measures when using muriatic acid in pools?
When using muriatic acid in pools, it’s crucial to wear recommended personal protective equipment such as goggles, safety glasses, and rubber gloves. The acid must be diluted at a ratio of at least 5:1, preferably 10:1, before adding to the pool. Always add acid to water when diluting, not the other way around. Large quantities of acid should be added to the pool all at once, but with caution to avoid damaging the plaster. Pour the acid over a return flow while the pump is running, then brush to ensure thorough mixing.
How should muriatic acid be added to the pool?
Muriatic acid should be added to the pool carefully and in a diluted form. It should be diluted at a ratio of at least 5:1, preferably 10:1, before adding. The acid should be added to water, not the other way around. When adding large quantities of acid to the pool, it should be poured slowly over a return flow while the pump is running, then brushed to ensure thorough mixing. This prevents the pH from getting too low in one spot, which could potentially damage the plaster. Personal protective equipment, such as goggles, safety glasses, and rubber gloves, should be worn when handling the acid.
What is the procedure for using muriatic acid in pools?
The procedure for using muriatic acid in pools involves several steps. First, test the water for metals and ensure that the total alkalinity is less than 140 ppm, hardness is less than 350 ppm, and pH is less than 7.4. Adjust if necessary. Then, turn on the pump and keep it running for the next 24 hours. Add half of the muriatic acid near a return line to ensure good mixing. Wait for about 20-30 minutes. Add the remaining muriatic acid in the same manner as before. Wait for 2 hours. Test the pH of the water. If it is very high, add 1 quart of muriatic acid. If the pH is light to dark red, add half a quart (1 pint) of muriatic acid. Wait for 2 hours. Test the pH again. Continue testing and adding 1 pint of acid each time until the pH is 7.4.
How to calculate the amount of muriatic acid needed for pools?
To calculate the amount of muriatic acid needed for pools, you need to consider the current pH level, the desired pH level, and the volume of the pool. For example, if you want to lower the pH level from 8.0 to 7.5 in a 16,800-gallon pool, you would need 21 fl. oz. of muriatic acid. This is calculated by multiplying the amount needed (21.0 fl. oz.) by the volume factor (1.68), giving a total of 35.28 fl. oz.
For a more specific calculation, such as adjusting alkalinity, you can use the formula (Current Alk – Desired Alk) / 10 * (Pool Volume / 10,000) * 25.6 fl oz = Acid Dose. For example, if you have a pool with 15,000 gallons of water, a current pH of 7.8, a current alkalinity of 180 ppm, a desired alkalinity of 100 ppm, and a CYA of 30 ppm, you would need to add 2.4 gallons of Muriatic acid to the pool.
How to Calculate the Required Dose of Muriatic Acid?
To calculate the required dose of muriatic acid, use the formula: 1.0 fl oz of muriatic acid per 2 oz of Borax or 2.8 gallons per 10 boxes of Borax. For example, if you have 973.5 oz of Borax, divide it by 2.12 oz of Borax per 1 fl oz of muriatic acid, which equals 459.2 fl oz. Then, divide 459.2 fl oz by 128 fl oz per gallon to get 3.59 gallons of muriatic acid. If you have 13 boxes of Borax, divide it by 10 and multiply the result by 2.8 to get approximately 3.7 gallons.
What is the Procedure for Using Muriatic Acid and Borax?
- Test the water for metals. If metals are present, remove them or use a stain inhibitor before proceeding.
- Ensure that the total alkalinity is less than 140 ppm, hardness is less than 350 ppm, and pH is less than 7.4. Adjust if necessary.
- Turn on the pump and keep it running for the next 24 hours.
- Pour about half of the Borax dose into a large bucket or container and break up any lumps with a scoop or other tool. In this example, we would use 6 or 7 boxes.
- Broadcast the powder into the water while walking around the pool using a scoop or plastic bowl.
- If any powder accumulates on the pool bottom, use a pool brush to help it dissolve.
- Add half of the muriatic acid near a return line to ensure good mixing. In this example, we would add 2 gallons.
- Wait for about 20-30 minutes.
- Add the remaining Borax in the same manner as before. In this example, we would add 6 or 7 boxes.
- Add the remaining muriatic acid as before. In this example, we would add 2 gallons.
- Wait for 2 hours.
- Test the pH of the water. If it is very high, the test will turn purple. In this case, add 1 quart of muriatic acid.
- If the pH is light to dark red, add half a quart (1 pint) of muriatic acid.
- Wait for 2 hours.
- Test the pH again. Continue testing and adding 1 pint of acid each time until the pH is 7.4.
What are the effects of high cyanuric acid levels in pools?
High levels of cyanuric acid in pools can slow down chlorine kill times and require higher levels of free chlorine for disinfection and oxidation. This can lead to slower disinfection rates and potentially allow for the growth of algae despite regular chlorine treatment. High cyanuric acid levels are not considered a health hazard, but they can affect the balance of chemicals in the pool and may require the pool to be drained and refilled to reduce the cyanuric acid level.
Does muriatic acid lower alkalinity?
Yes, muriatic acid can lower alkalinity.
Muriatic acid is often used to lower the total alkalinity in pool water. The amount of muriatic acid needed can be calculated using specific formulas. For example, to lower the total alkalinity by 10 ppm in 10,000 gallons, 25.6 fl oz of Muriatic Acid is added. The desired change in alkalinity is calculated by subtracting the desired alkalinity from the current alkalinity. This change is then divided by 10 ppm, the pool volume in gallons is divided by 10,000, and the result is multiplied by 25.6 fl oz. This calculation-based method allows for precise adjustments of pool alkalinity.
How to Lower Total Alkalinity with Muriatic Acid?
To lower total alkalinity with muriatic acid, you can use the following formulas: divide by 125,000 and multiply by the change in ppm, or divide by 500,000 and multiply by the change in ppm. For example, if you have a pool with 15,000 gallons of water, a current pH of 7.8, a current alkalinity of 180 ppm, a desired alkalinity of 100 ppm, and a CYA of 30 ppm, you would calculate (180 – 100) / 10 * (15,000 / 10,000) * 25.6 fl oz = 307.2 fl oz or 2.4 gallons. So, you would need to add 2.4 gallons of Muriatic acid to the pool to lower the alkalinity by 80 ppm.
Does Muriatic Acid Lower pH Levels?
Yes, muriatic acid does lower pH levels.
Muriatic acid, also known as hydrochloric acid, is used to lower the pH and total alkalinity in water. The amount of muriatic acid required depends on the desired decrease in pH level. For instance, to lower the pH from 8.0 to 7.5, 21 fl. oz. of muriatic acid is needed. Acidic pool chemicals like muriatic acid lower pH, while basic pool chemicals like soda ash and sodium bicarbonate raise pH. The rate and ease of pH change can vary and are determined by the total alkalinity.
How much muriatic acid is required to lower pH by 0.1 at different levels of Total Alkalinity (TA) and Cyanuric Acid (CYA)?
The amount of muriatic acid required to lower pH by 0.1 at different levels of Total Alkalinity (TA) and Cyanuric Acid (CYA) varies. When the pH is 7.1, TA is 100 ppm, and CYA is 0 ppm, 8.7 fl oz of acid is needed. If CYA is 30 ppm, 9.18 fl oz of acid is required. When CYA is 50 ppm, 9.82 fl oz of acid is needed. If CYA is 100 ppm, 11.45 fl oz of acid is required.
These quantities are based on a chart that displays the amount of muriatic acid needed to decrease the pH by 0.1 when TA is 100 ppm and CYA is at 0, 30, 50, and 100 ppm. The amount of acid needed increases as the level of CYA increases. For example, when CYA is 30 ppm, 35 times more acid is needed than when there is no CYA and no alkalinity, and 5% more acid than when TA is 100 ppm and CYA is 0 ppm. Similarly, when CYA is 50 ppm, 38 times more acid is needed than when there is no CYA and no alkalinity, and 13% more acid than when TA is 100 ppm and CYA is 0 ppm. When CYA is 100 ppm, 44 times more acid is needed than when there is no CYA and no alkalinity, and 32% more acid than when TA is 100 ppm and CYA is 0 ppm.
How to Adjust pH and Total Alkalinity (TA) in a 10,000 Gallon Pool with Muriatic Acid?
To adjust pH and Total Alkalinity (TA) in a 10,000-gallon pool, you need to follow the pH-Total Alkalinity Adjusting Chart. This chart provides the amount of Muriatic Acid needed and the subsequent aeration required for different pH and TA levels. For example, if the pH is between 6.5 and 8.5 and the TA is 320 ppm, you need to add 588 fl oz of Muriatic Acid and then aerate the pool. The amount of Muriatic Acid increases as the Total Alkalinity increases. After adding the Muriatic Acid, aeration is necessary to help distribute the acid and adjust the pH and TA levels.
| pH | Total Alkalinity (ppm) | Muriatic Acid (fl oz) | Action |
| 6.5 – 8.5 | 320 | 588 | Aerate |
| 6.5 – 8.5 | 340 | 639 | Aerate |
| 6.5 – 8.5 | 360 | 690 | Aerate |
| 6.5 – 8.5 | 380 | 741 | Aerate |
| 6.5 – 8.5 | 400 | 792 | Aerate |
How does Muriatic Acid impact pool water balance?
Muriatic Acid impacts pool water balance by reducing pH and total alkalinity in water. It is the most commonly used substance for this purpose. When added to a pool, it can lower the pH from a higher level to a more desirable level. For instance, adding 35.28 fluid ounces of muriatic acid to a 16,800-gallon pool can lower the pH from 8.0 to 7.5. However, it’s important to note that concentrated muriatic acid can severely damage certain types of pools and must be diluted before adding. It’s also crucial to wear recommended personal protective equipment when handling this chemical.
