Is High pH Bad For Pools?
Properly balancing the pH in your swimming pool is one of the more challenging individual tasks involved with pool maintenance. The dynamic nature of how pH and total alkalinity are intertwined combined with ever changing chemistry values for both measurements is a huge source of frustration for pool owners. The pursuit of neutrally balanced water can prove too challenging for many pool owners causing them to give up on maintaining the water in the optimal 7.4 neutral range. Is it really a big deal if the pH of the water is 8.0 or over?
The first thing you need to appreciate as a pool owner asking questions about pH balance is that the pH scale is logarithmic. A pH of 8.0 is ten times as alkaline (basic) as a pH of 8.0. If you have managed to achieve a pH of 9.0, which I hope you have not, then this would represent the water being 100 times more alkaline than a pH of 7.0 and this is why your pH values for the water matter so much. To the uninitiated the difference between seven and eight sure doesn't sound like a big deal, but saying it a different way highlights the severity. What if the pH was 5.0 instead of 7.0? Well that means the water would be 100 times more acidic than a pH of 7.0. It sounds fairly insidious when you say it that way. Operating your pool with a pH chronically tens times higher than what the pH should be will have both short and long term ramifications.
The pH of your water is one of the main factors considered when calculating the saturation index for your pool water. Saturation index is the calculation to determine whether the water is in an acidic state, a neutral state or a scaling state.
With a high pH value it is very likely that your water is in a scaling state which will promote scaling on surfaces of the pool as well as scaling within the filtration equipment. This scale development can shorten service life of components such as the heat exchanger in your gas heater, and can also cause problems to develop on your pool surface from scale formation.
Swimming in pool water with a high pH - Every person is different however some people are sensitive to pH imbalance in water they swim in. In fact it is widely known in the pool industry that many people who complain of being allergic to chlorine are actually not allergic to chlorine, but sensitive to changes in the pH of the water. Having adverse pH levels can result in dry skin, rashes, red eyes, itching and general discomfort after swimming. While some people may have no problems with swimming in high pH water it is possible that other people will experience problems in the same pool.
Chlorine effectiveness at high pH levels - One of the most important reasons to not let your pH be chronically high is due to the fact that chlorine is effective at much lower ranges than what pool water is maintained at. In an ideal sense chlorine would work best in pH similar to coffee, or an environment 100 times more acidic than what the optimal range for pool water is. Unfortunately people tend to not be very comfortable in water that acidic so we match the pool water to closely match our own pH levels. While chlorine is most effective at a lower pH, it is still very effective in the neutral pH range, optimally 7.4, chlorine is largely ineffective in water more alkaline than this. Over 8.0 there is a marked decrease in the effectiveness of chlorine, and above a pH of 8.4 chlorine is almost completely ineffective. You can still measure the free chlorine level in the water, but the water will not be properly protected and the chlorine may not be able to kill bacteria and organic matter growth like it is supposed to.
Long term damage to pool from high pH
When you allow the pH of your pool water to be chronically too high this likely results in a "scaling state" according to the saturation index calculation. Over a long period of time this scale development can lead to early failure of things like your heat exchanger. The scale builds up a physical layer on the heat exchanger which causes the exchanger to overheat. The scale itself also promotes advanced rates of corrosion. Inside of a swimming pool high pH can lead to water quality problems from a lack of effective sanitizer, but it can also cause precipitated scale to form on the interior surface of your pool. This rough scale texture further promotes algae growth and can cause staining and physical damage to pool surfaces.
Tips For Balancing pH In Pool Water
It might be a challenge to learn how to properly manage and balance your pH however this is a challenge that you must take on to protect your pool and protect the swimmers in your pool. It is extremely common to see pool owners who have a pH level above 8.0 every single day. This is especially true for owners of salt water swimming pools which are known to have chronic high pH issues. The solution to balancing your pH is to follow the industry accepted protocol of adjusting the total alkalinity first, followed by the pH, and understand that when you make a downward adjustment to the pH this will also drag the alkalinity down.
If you had an alkalinity measurement of 75 ppm but you wanted to adjust the pH down you would need to first raise the alkalinity level, knowing that the alkalinity will drop again when you add acid to lower the pH. The higher your alkalinity level, the more the water will resist fluctuations in the pH level. For more information on the relationship between pH and total alkalinity you can read the pool chemistry crash course.
Borates to help maintain neutral pH - If you have a pool that has chronically high pH and you do not seem to be able to get it under control then you might want to look towards using borates in order to help buffer your pH movement. Borates help your water to resist upwards drift of your pH. When borates are added and maintained at 50 ppm in a pool this will help to lock in the pH and alkalinity values. Simply get the pool into balance for pH and total alkalinity, and then add 50 ppm of borates. This will reduce the amount of pH drift you experience, and in many cases work as a permanent solution against chronically high pH.
Waterfalls increase pH levels - One of the only ways to adjust pH without changing the total alkalinity of the water is aeration. Having a waterfall, sheer descent, bubblers, deck jets or any other form of water aeration will substantially increase the pH of your pool water. If you were to leave your waterfalls running all of the time your pH would very likely be way too high. If you are struggling to keep your pH levels down then be sure to turn off your waterfalls and water features when you are not using the pool.
Being able to control the pH of your pool and maintain the water in a neutral state is critical to the long term performance of your pool and pool equipment...not to mention both the comfort and the safety of the swimmers in your pool. It might seem like an innocuous problem to have a pH that is usually too high, but it definitely would be a mistake to accept this problem over the long term. Having a neutrally balanced pH to your water is actually one of the single most important, fundamentally parts about maintaining your pool.
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