Maintaining the right total alkalinity in pool water is important because it helps the water resist sudden changes in pH and keeps chlorine working effectively. Alkalinity is the ability of water to neutralise acids, and it comes from alkaline salts like calcium and magnesium. The recommended range for swimming pools is between 100–150 ppm (parts per million), but if it gets higher, the pH can drift upward, making the water cloudy and unstable. This affects the stability of disinfectants, preventing them from doing their job in sanitizing the pool. High alkalinity can also impact pool finishes, leading to deposits that make surfaces rough over time.
To fix high alkalinity, you can use muriatic acid or sodium bisulfate, also known as a pH reducer. Begin by measuring the TA levels with a sample test kit to see if they fall within the ideal range. If needed, add the desired amount of acidic substance carefully, as it will react with the water to lower the alkalinity. After adding, aerate the water to help the pH stabilize within 7.2–7.8, preventing it from becoming less stable. Regular measurements are key to controlling alkalinity and ensuring that pools, hot tubs, and aquariums stay clean and safe for people to enjoy without health risks or damage to surfaces.
What is Total Alkalinity?
Maintaining total alkalinity is important because it acts as a buffer, helping to prevent drastic fluctuations in pH levels. Alkalinity measures the pool’s ability to resist acidic changes and keep a consistent balance. It is a parameter that works in relationship with pH, as both are crucial for water chemistry. The levels should be between 80-120 ppm (parts per million) to keep water safe. If it’s higher or lower, it can affect the ability of chlorine to sanitize effectively and may damage the pool’s equipment like pool tiles over time.
The Environmental Protection Agency (EPA) provides guidelines on maintaining proper water quality and ensuring that swimming pools meet safety standards. High alkalinity increases the buffering capacity, making it harder to adjust the pH level, while low alkalinity leads to acidic water that corrodes surfaces. The solution to maintaining the right balance involves adding the correct measure of acid to neutralize excess alkalinity without disrupting the neutral buffer system.
How Do Alkalinity and pH Affect Each Other?
When total alkalinity is too high, it acts as a buffering agent, making it hard to adjust the pH. This can cause an elevated pH level, reducing the effectiveness of chlorine and making the water cloudy. Keeping alkalinity in the normal range (80-120 ppm) helps stabilize the pH and lets chlorine do its sanitizing job properly. If alkalinity is too high, use a chemical like muriatic acid or sodium bisulfate to bring it down gradually. Adding acid in one spot can cause the pH to drop too much, so pour it slowly while circulating the water to maintain balance.
What Causes High Total Alkalinity?
If your pool has high total alkalinity, it might be because of the pool chemicals you use or how often you add them. Some chlorine products, like stabilized ones, contain cyanuric acid, which helps keep chlorine levels stable but can also increase alkalinity. Hard water with minerals can also affect the balance, especially in areas with heavy water usage. A bather load that’s too high and frequent chlorine shock treatments can make the pH fluctuate, leading to imbalance. Similarly, using the wrong stabilizer or not checking pool pH levels regularly can cause problems. The number of common mistakes people make, like adding the wrong amount of acid or not testing often, can raise the risk of unstable alkalinity. If you just throw in chemicals without knowing their impact, your pool could end up needing more adjustments.
Cyanuric Acid
Using cyanuric acid (CYA) in a pool is essential, but it can impact total alkalinity if not managed properly. This chlorine stabilizer prevents the chlorine from evaporating under the sun’s UV rays, acting as a buffer against rapid acidity changes. However, high CYA levels can lead to buffered and overly stabilized pool water, making it hard to adjust chemistry levels. Since trichlor contains cyanuric acid, using it too often can raise total alkalinity. To keep levels balanced, you should routinely test with test strips or a liquid test kit to ensure the water stays healthy and properly sanitized.
Low Sanitizer Levels
Yes! When chlorine levels drop too much, it can let contaminants build up in the water. This is common when there’s a high bather load—more swimmers mean more waste like sweat, oils, and sunscreen. With low chlorine, these impurities thrive, causing chemical imbalances that push total alkalinity higher. Plus, weak sanitization can mess with the pH, making it harder to control alkalinity. Regularly checking and balancing your chlorine levels can prevent this problem and keep your pool safe and clear.
Pool Shock Causes
Many pool owners are surprised to notice that their total alkalinity levels rise after using chlorine-based pool shocks. This happens because some pool shocks contain highly alkaline compounds that can raise both pH and alkalinity levels in the water. If used on a regular basis, these high alkaline additives may cause balancing issues. Therefore, it’s important to test and adjust the pool chemistry regularly to prevent unwanted spikes in alkalinity levels.
What Happens if Your Pool Alkalinity is Too High?
When total alkalinity in a pool is too high, it prevents the pH from drastically changing, but this stability comes at a cost. High alkalinity can lead to cloudy water, an unattractive appearance, and calcium buildup on pool coping, which may be absorbed into surfaces, creating a stubborn phenomenon known as scaling. This situation can be bad for both the effectiveness of chlorine and the cleanliness of the water, as it becomes difficult to lower the pH and maintain a balanced pool. The Centers for Disease Control and Prevention (CDC) recommends keeping alkalinity within 7.0 to 7.8 to ensure chlorine stays an effective disinfectant, killing germs while keeping the water safe for swimmers. If the level goes higher, the hardness of the water can result in clogged filters, restricted flow, and damage to pool equipment.
Aside from affecting swimming conditions, high alkalinity can also cause skin irritation, burning eyes, and discomfort for people using the pool. Over time, it can shorten the life of bathing suit fabric, goggles, and other accessories, making everyone’s experience worse. Because alkalinity resists changes in pH, trying to achieve a lower range requires more chemicals, which hits your pocketbook hard. Some may attempt to use naturally available sources like baking soda, but that actually works to raise alkalinity, not lower it. The factors contributing to high alkalinity may differ, but dumping the wrong materials can make things overly complicated. Monitoring and adjusting the pool regularly is the first order of business for keeping it stable, clean, and safe while avoiding expensive remedy costs.
Can Alkalinity Be Lowered Without Affecting The pH Level In Pools?
Lowering the alkalinity in a pool without affecting pH is a challenging task because both are closely related. When attempting to reduce the total alkalinity level, adding acid can cause a sharp drop in pH, making it unstable. The most realistic way to balance both parameters is through aeration, which helps raise the pH naturally without increasing alkalinity. By creating water turbulence, like using the pool return system or running the pool pump at full capacity, the surface area of the water expands, allowing CO2 to outgas. More disturbance on the water’s surface, such as using an air compressor with a long hose placed in the deepest part of the swimming pool, can speed up the process. Pool owners can also use a spa blower through the return line to boost aeration. This method ensures that the pH is increased dramatically without affecting the stable total alkalinity level in their hot tub or pool.
How to Lower Alkalinity in a Pool
Using the right method to lower total alkalinity in pool water is important to keep the pH level stable and avoid negative consequences like fluctuating levels. The most common reason for high alkalinity is the rising pH, which can spiral out of control if not addressed. To bring it back to the ideal alkalinity range of 100-150 parts per million (ppm), you can use muriatic acid or sodium bisulfate, both effective pH reducers. The best action is to first check the current alkalinity and pH levels in your pools or hot tub, then slowly add the chosen chemical while circulating the water. Leading pool chemical manufacturers like Clorox Pool & Spa or HTH Pools provide high-quality solutions for maintaining balanced water chemistry. Below you’ll find key information on lowering alkalinity safely while keeping the balance right and avoiding rising pH.
How to Use Muriatic Acid to Lower Alkalinity
Using muriatic acid (also known as hydrochloric acid) is one of the best ways to lower total alkalinity in your pool. This acid is extremely corrosive and dangerous, so it’s important to protect yourself by wearing safety equipment like a mask, goggles, face shield, and gloves before handling it. Always read directions on the bottle and follow the manufacturer’s directions carefully to avoid mishandled usage. Since different brands may have different concentration levels, comparing products and their recommended amounts is crucial before adding them to your pool.
To start, turn off the pool pump to stop moving the water. Calculate how much full-strength muriatic acid you need by using a chart or following the general rule—25.6 ounces of acid will reduce total alkalinity by 10 ppm in a 10,000-gallon pool. Dilute the muriatic acid in a bucket of water before pouring it into the deepest area of the pool. Then, let it sit still for at least an hour to let the acid spread naturally without the pump running. After the elapsed time, turn the pool pump back on and let the water circulate for about 5 hours before testing again to see if the pH levels have dropped within the ideal range.
If the pH is too low, you may need to raise it using aeration. You can use an aerator, fountain feature, or other methods to introduce natural aeration without impacting other chemicals. However, avoid over-aerating, as it can disrupt the chemistry of the pool. If the pH levels still aren’t within range after a week, you may need to repeat the process in several rounds. This step requires patience, as lowering total alkalinity too quickly can cause calcium deposits to form on filters, concrete, and bricks around the pool.
For those concerned about handling muriatic acid, an alternative is sodium bisulfate, a less corrosive option found at hardware and home supply stores. Whichever method you choose, using a smartphone app to check real-time results can help you maintain a balanced chemical environment and enhance your routine. Keeping your pool in check ensures a safe, enjoyable swimming experience without unexpected chemical issues before scheduled parties.
How to Use Sodium Bisulfate to Lower Alkalinity
Sodium bisulfate, also called dry acid, is a safer alternative to muriatic acid for lowering alkalinity in your pool water. First, check the pH levels and calculate the right amount of pH reducer using the directions on the product. Fill a bucket 3/4 full with water and slowly add the acid salt while stirring with a wooden stick. Ensure the granules are fully dissolved before pouring the solution around the perimeter and the deep end of the pool. Avoid letting undissolved particles sink to the bottom, as they can destroy the surface. Let the water circulate and then retest the levels after a few hours. If needed, repeat the procedure. Store the pH decreaser in a dry place away from moisture, as it can become expensive if ruined.
Other ways to balance pool pH
Keeping pool alkalinity in check isn’t as complicated as it seems, but neglecting it can cause pH levels to fluctuate, leading to corrosion on metal parts and stains on surfaces. A malfunction in filtration systems or a lack of adequate maintenance can make the water too acidic, resulting in stress on equipment and irritation to the eyes, nose, throat, and skin. Using trichloroisocyanuric acid tablets improperly can worsen instability, making the pool appear green due to inefficient disinfection and algae growth which can eventually make you sick over time. To increase or decrease pH safely, follow the recommended approach—calculate the pool’s volume, determine the right dosage indications, and apply a pH increaser like sodium bicarbonate at the right time. Achieving the desired results requires greater precision, so always follow the essential steps carefully.
Frequently Asked Questions (FAQ’s)
1. How do you bring down the alkalinity in a pool?
Using acidic products like pH reducers helps balance alkalinity. These compounds react with water, changing its acidic properties. Adding carbonated solutions can aid in expelling carbon dioxide, preventing a rise in pH. Also, avoid excessive bicarbonate use, as it can produce carbon dioxide and keep alkalinity high.
2. What happens if alkalinity is too high in pool?
Too much alkalinity in a pool can cause scaling on the surface and plumbing. It can also damage equipment and make the water cloudy. High levels disrupt chlorine, reducing its power in keeping the pool free from harmful bacteria, making proper balance necessary.
3. How can I lower alkalinity without lowering pH?
The best way to lower alkalinity without dropping pH is by aerating water. Aeration creates turbulence, which causes carbon dioxide (CO2) outgas. This helps increase pH naturally without needing chemicals. Unlike adjusting pH vice versa, this method keeps balance while avoiding sudden chemical changes.
4. Does baking soda lower pool alkalinity?
No, baking soda (sodium bicarbonate) does the opposite. It makes pool water more alkaline and can raise alkalinity above pH 8. Many commercial pool products utilize it as an active ingredient for stability and clarity. If improving low alkalinity, adding it is the main approach.
5. Will shocking pool lower alkalinity?
Shocking a pool boosts chlorine levels and kills contaminants in the water but doesn’t directly impact total alkalinity. To lower alkalinity, you need to use specific chemicals that adjust pH. Shock treatments focus on sanitation rather than balancing alkalinity.
