It is very common for chemical additives and contaminants to cause swimming pool water to become too basic, which means that it will have a very high pH. The Centers for Disease Control and Prevention (CDC) recommend keeping pools at a pH level between 7 and 8, to avoid irritation to the eyes and skin, keep them in a hygienic state, and avoid damage to them and their facilities. Measure your pool water frequently to detect if its pH is too high. You can reduce it with a chemical additive such as muriatic acid or sodium bisulfate or install a CO2 system that maintains an ideal pH.
Measure The pH Of Your Pool
Get a DPD measurement kit. There are many types of kits available for measuring the pH of swimming pools (including digital meters and litmus strips), but DPD kits are some of the most accurate. These are also less expensive than digital kits. You can find them at most department and home supply stores. These contain various chemicals that will change color when mixed with the pool water. These chemicals will measure different elements of the water, such as pH, total alkalinity, chlorine and bromine levels, and water hardness.
These kits can be available in different forms. For example, some will use liquid reagents, while others will use solid tablets. Liquid and tablet measurement kits will have a similar level of accuracy, but the latter may be easier to use since you won’t have to accurately measure liquid reagents.
Litmus strips are easier to use than DPD kits, but the latter is more accurate when used correctly.
Digital measurement kits will not have an obvious way to determine if the results are inaccurate so their results can be misleading.
How To Use A DPD Kit
To use a DPD kit, you will have to mix different chemical reagents with pool water samples. These chemicals will change color when added to the water, and you will need to check the color chart to interpret the results. Please read the directions carefully to ensure that you use the kit and interpret the results correctly. Verify that you are using the correct reagent to measure pH levels. Most kits use phenol red for this purpose.
Beware Of False Or Problematic Results
Most swimming pool pH meters will appear more yellow at low pH levels, and redder at high levels. However, if your pool water contains very high chlorine or bromine levels, this could hamper measurement and lead to unusual results (such as turning purple). If the water has very low alkalinity, this could also lead to incorrect results. You can minimize these problems by measuring chlorine, bromine, and total alkalinity before pH.
Measurement kits can also produce incorrect results if reagents are improperly stored (eg, in humid areas or extreme temperatures) or if they are cross-contaminated by careless handling.
Test Your Pool Water At Least Twice A Week
Most pool experts recommend testing your compounds 2-3 times a week, especially during the summer, as these are used more frequently during that period. The CDC recommends testing them twice a day or even more frequently during periods when they are used daily or when many people use them throughout the day.
You will need to check the pH of the pool more frequently if the pool is used a lot, as the chemical composition of the water will be affected by everything that enters the pool (including natural oils from swimmers’ hair and body, traces sunscreen, and other body care products or dirt left on it).
Lower The pH With Muriatic Acid
Purchase muriatic acid with a formula designed for use in swimming pools. This is also known as hydrochloric acid, and it is a corrosive chemical with many uses in the home. You can ensure that you get the proper concentration for use in pools by purchasing a product that is promoted as a pool chemical. Most pool and home supply stores will offer muriatic acid for this purpose.
Read the directions on the label carefully. You will find products in various concentrations and forms. Some muriatic acid pH reducers are marketed as pre-mixed liquid solutions, but there are also others in granules. Read all the safety instructions and learn the exact way to use the specific product before adding it to the pool. Some types of muriatic acid may be added directly to the pool, while others may need to be diluted in a bucket of water before use.
Take proper safety precautions. Even dilute muriatic acid can burn your skin and eyes. It can also irritate your nose, throat, and lungs if you inhale its gases. Before handling this compound, you should put on rubber gloves and clothing that covers your arms, legs, and feet. Wear a respirator and safety gloves. Always use the acid in a well-ventilated area. If muriatic acid gets in your eyes, you should immediately wash it off with cool, cool water for a minimum of 15 minutes, and then seek medical attention.
If the acid comes into contact with your skin, you will have to wash it with cool, cool water for a minimum of 15 minutes, and remove any clothing that has stained. You will have to seek medical attention upon completion. You should see a doctor immediately if you ingest acid or inhale its gases.
Determine how much acid to add. Read the directions on the product label to determine how much acid to add based on the size of the pool and the current pH level of the water. Add about ¾ of the recommended amount to avoid lowering the pH too much.
Pour the acid into the pool’s return spout. Keeping the return nozzle running and the vent facing downward, slowly and carefully pour the required amount of acid directly onto the nozzle. The return flow will distribute evenly throughout the pool. Keep the container close to the water as you pour in the acid so that it splashes as little as possible. Prevent the acid from falling on any part of the pool or coming into direct contact with the walls of the pool.
Recheck its pH after 4 hours. You will have to do it again once the muriatic acid has circulated. If it is still very high, you will have to repeat the procedure using the amount of acid recommended for the new pH level.
To swim, you will have to wait at least 4 hours after the last acid application. Before entering the pool, you should wait long enough for the acid to distribute evenly in the water. Otherwise, you run the risk of running into concentrated acid spots in the water. Keep the pump on and the nozzles active while you wait for the acid to cover the water.
Lower The pH With Sodium Bisulfate
Purchase sodium bisulfate or “dry acid” for the pool. This is an acid available in granules or powder. It has the advantage of being a bit safer and milder than muriatic acid. Sodium bisulfate for swimming pools can be found at most home and pool supply stores.
Follow the directions on the package. Each manufacturer may provide different instructions for use. In some cases, you may have to dissolve the sodium bisulfate in water before adding it to the pool, while other products may have to be added directly as a powder. Determine how much sodium bisulfate to add. Follow the manufacturer’s directions to determine the correct amount to use based on the pool’s size and current pH level. You may need to use 3/4 of the recommended amount to avoid reducing the pH too much.
Take safety precautions. Sodium bisulfate is relatively mild, but it can still cause severe burns and irritation. Wear gloves and clothing that covers your skin, such as long sleeves and long pants. Always handle compounds in well-ventilated areas. If you’re concerned about the wind blowing acid granules toward your face, you can use safety glasses or a face shield. If the sodium bisulfate gets on your skin, you will need to wash it well with soap and water. See your doctor if you develop skin irritation that doesn’t go away after washing.
If this compound gets into your eyes, you will have to wash them with cold water for a minimum of 15 minutes and then seek medical attention. If you do ingest the powder, you should rinse your mouth and drink at least a large glass of water. You will need to seek medical attention immediately.
Pour the dry acid into the pool’s return nozzles. Keep the pump on and the nozzles active, and slowly add the acid directly through the return nozzles. Keep the powder away from the skimmer. Get close to the water when you pour it and be careful not to let the wind blow the dust towards you.
Wait a few hours and re-measure the pool’s pH. Wait 4 hours for the acid to circulate and measure again. Sodium bisulfate can also reduce the total alkalinity of your pool, so it will be important that you also measure it and verify that it is still in an acceptable range. Make any necessary changes based on the measurement results. To re-measure the pH levels, you shouldn’t wait more than 24 hours after adding the dry acid.
Add an element that increases alkalinity, if necessary. If the total alkalinity level in your pool is too low after adding the sodium bisulfate, you will need to raise it by adding an element to the water for that purpose, such as baking soda or sodium sesquicarbonate. You can find these products at most home and pool supply stores.
Sodium carbonate may also raise the alkalinity of the pool, but it could cause the pH to rise too high again. Follow the manufacturer’s directions to determine the amount of these products to add based on the size of the pool and its current alkalinity level.
Wait at least 4 hours before swimming. Sodium bisulfate is relatively mild, but it can still irritate your skin and eyes. Before swimming, you should wait long enough for the acid to dissolve and circulate throughout the pool.
Install A CO2 System In The Pool
Buy a CO2 system to control the pH more safely. Carbon dioxide (or CO2) can safely and effectively lower and stabilize the pH. There are various CO2 systems available for swimming pools, some of which will be able to automatically analyze the pH and modify its intensity accordingly. You can find these devices in stores that specialize in supplies for pools.
Some of these systems are fully automatic, while others will need to be controlled manually. Consult with a specialist at a pool supply store, so you will know which type of CO2 system will be the most suitable for you. These devices can be expensive. In the US, these can cost between $ 300 and $ 10,000. However, these could save you money by reducing the need for frequent pH and chlorine changes.
Have a professional install the system. It is probably best to entrust this work to a swimming pool technician unless you have a lot of experience in the installation of this equipment. You can consult with a professional before buying the system, so you will know if it is suitable for your pool.
Do not use a CO2 system if your water has a high mineral content or high total alkalinity. CO2 can raise the total alkalinity of a swimming pool, so it is best not to use these systems if the water is already at these high levels (that is if the measurement indicates that it has a value of more than 125 ppm). Also, CO2 will lower the pH less effectively if the water has high mineral content. Consult with a swimming pool technician to determine if the water conditions are correct for a CO2 system.
You could have a hard time maintaining a good chemical balance in your pool. If you are unsure whether you can change the pH on your own, you should contact a swimming pool technician for advice and assistance.
Always keep muriatic acid and sodium bisulfate out of the reach of children and pets.