Is It Safe To Swim In A Pool With High Alkalinity?

Total alkalinity is a significant metric that, while influencing pH, is distinct from pH. The amount of alkaline compounds in your pool’s water is measured by its total alkalinity. Alkaline compounds can cause an uncontrollable shift in the pH of your pool’s water.

Alkalinity levels in a pool can have dangerous effects not only on the pool but also on the swimmers’ bodies. High alkalinity levels in a pool cause calcium scaling and cloudy water, which is a major breeding ground for microbes.

These microbes can cause health problems, such as gastroenteritis, ear, nose, and throat infections for swimmers.

When total alkalinity is low, the water becomes aggressive, causing rapid pH changes. When it’s too high, it produces cloudiness, lime precipitation, and difficulty adjusting the pH.

It is critical to stick to the 60-100 ppm guideline for daily or “shock” chlorination, as well as the 90-125 ppm standard for weekly chlorination and Halobrom, to maintain optimum total alkalinity. Sodium bisulfate can lower total alkalinity, and sodium bicarbonate can raise it.

Is it safe to swim in a pool with high pH?

Different pH levels might be hazardous not just to your swimming pool but also to your health. A swimming pool with a high pH is alkaline, and this can pose problems for the pool and the swimmers.

If the pH level in your pool is higher than 7.8, you might expect hazy water and scaling along the pool walls. Furthermore, a pH that is higher than normal hinders chlorine and other disinfection chemicals from working properly.

Bacteria and other germs may thrive in your pool as a result of this. Bacteria in your pool water can be hazardous when they enter your body, even if you can’t see them with your naked eye.

There are various possible explanations for what produces high pH in a pool, such as a fast increase in water temperature. But the causes are less relevant than the effects.

Is swimming in a pool with imbalanced pH safe for the eyes?

Swimming in a pool with an imbalanced pH is hazardous to the eyes, as it causes redness and irritation of the eyes. A swimming pool with an incorrect pH balance will cause your eyes to burn.

The human eye has a pH of 7.4. The eyes are more relaxed and without irritation when the pH balance of the pool is between 7.2 and 7.8, which is the recommended pH level of a pool.

Any pH level aside, that makes swimming in the pool totally unsafe for the swimmers’ eyes. Your eyes may begin to burn or feel uncomfortable in the pool if the pH is outside of this range.

To most people, it is unclear what causes someone’s eyes to burn when they are swimming in a pool.

The majority of people believe that if their eyes burn while swimming in a pool, it is because of chlorine. In actuality, ocular irritation is produced not just by chlorine, but also by an imbalanced pH level.

What causes high alkalinity?

Alkalinity levels in pool water can fluctuate due to a variety of factors. These can be natural or chemical.

Some of these changes may result in a rise in pool alkalinity, while others may result in a fall. Your alkalinity increases and falls in lockstep with your pH levels.

In the pool, alkalinity functions as a buffer to keep pH levels stable, which is crucial to avoiding scaling and other pool issues. Total alkalinity, or the amount of alkaline chemicals in the water, is how pool alkalinity is determined.

The bicarbonate alkalinity is the material that needs to be controlled in a swimming pool. It should be between 80 and 120 parts per million (ppm) (parts per million).

Alkalinity levels rise as a result of:

  • Sunblock, oils, alcohol, and other compounds raising pH and alkalinity levels.
  • Also, pool owners frequently tend to over shock their pools after a busy weekend, which can cause a fluctuation in the pools’ alkalinity. The strong alkaline component of pool shock causes levels to naturally climb.
  • Excessive precipitation entering the pool and diluting the water might result in a pH drop, similar to acid rain, lowering your pH and alkalinity levels.

What happens if pool alkalinity is too high?

Pool water with high total alkalinity can appear hazy and develop scale deposits on the pool’s sides, pool equipment, and piping. Scale can be removed, but it’s a complex procedure, and the chemicals used to do so take several weeks to work.

High alkalinity also causes the pH level of the pool to rise, eventually resulting in a lock scenario where adjusting the pH level up or down is extremely difficult.

So If the water in your pool is murky or your pool filters appear to be clogged with calcium deposits, your pool may have high alkalinity levels and require attention.

How to lower pool alkalinity?

Bringing a swimming pool‘s excessive total alkalinity and pH down to acceptable levels. Simply add muriatic acid to reduce total alkalinity and pH, then aerate the pool to restore pH balance.

Apply muriatic acid using the following steps:

  1. Use a dependable test kit and take accurate alkalinity and pH values.
  2. Muriatic acid should be diluted and evenly distributed around the pool. Use a pool calculator to calculate the exact amount of acid required. The alkalinity level you should aim for is 100 ppm.
  3. Allow the pool water to spontaneously aerate without the use of aerators such as spa jets, waterfalls, fountains, return points, air compressors, and other similar devices. If the pH falls too low, aeration can help raise it. The pH level that is recommended is around 7.4 or 7.6.
  4. To ensure that all chemicals are balanced, take measurements after six hours, then after 24, then after 48 hours. If you’re lucky, the pH level will not go below the normal range, and you won’t have to do anything else.
  5. Use an air compressor if pH levels are still too low after 48 hours and you want to speed up the procedure.

How to Lower Alkalinity Without Lowering pH

Along with the other issues, we outlined earlier, high alkalinity can make it difficult to correct pH. You’ll need to add an acid, most frequently muriatic acid, to lessen the alkalinity.

The challenge with adding acid is that lowering alkalinity without lowering pH is nearly impossible.

You may lower your pH to a hazardous level if you add enough muriatic acid to lower the total alkalinity to an acceptable level. There is, however, a method around this.

Adding acids to lower total alkalinity will always result in a lower pH. A two-step method is required to reduce total alkalinity without reducing pH. To begin:

Step 1

Gradually increase the acid until the alkalinity reaches the desired level. Don’t be concerned about the pH. Simply dilute the acid with water (in a bucket, for example) before pouring it, and walk it around the pool rather than putting it all in one spot.

This will prevent the pH from dropping too low in one location, which can harm the pool lining and etch the plaster.

Step 2

You must boost your pH without increasing your alkalinity after the alkalinity is correct. Simply aerate the pool to do this. The objective is to provide as much surface area as possible for your pool water.

One way to achieve this is to point your returns up toward the water’s surface and run your pump on high. This will cause turbulence on the water’s surface.

Use an air compressor with a long hose that ends in a weighted air diffuser at the bottom of the deep end for even more water disturbance. You can also add a spa blower to the return pipe of your pool.

Aerating your pool, regardless of how you do it, will boost the pH without impacting the alkalinity.

What causes a rise in ph and total alkalinity in a swimming pool?

  • The use of Calcium Hypochlorite (powder chlorine) pool shock to disinfect pool water is the second source of elevated pH in a pool. Cal Hypo has a high pH and calcium level, and if you don’t take steps to balance your pH, it will drastically raise the pH in your pool.
  • The water supply could also be to blame for the extraordinary spike in total alkalinity. It’s likely that the alkalinity of your pool fill water is already high, and that mixing it with more alkalinity increaser will enhance your overall alkalinity. If your water source has high total alkalinity, test it for alkalinity and use a new source because you’ll have to apply more dry acid to lower both pH and total alkalinity in your pool.

It’s difficult to get a perfect pH and alkalinity balance because acid lowers both, but not at the same rate. If your pool has a high pH and total alkalinity, here is the simplest approach to lower and balance pH and total alkalinity without requiring any additional equipment like an aerator.

  • Keep a close eye on your alkalinity levels to avoid pH and total alkalinity concerns.
  • To minimize pH and calcium scaling, you must use extreme caution when disinfecting your pool with granular chlorine.
  • High alkalinity is one of the main reasons why the pH in a swimming pool climbs over the recommended limit. To avoid high alkalinity, carefully add an alkalinity increaser while measuring its level, and make sure your total alkalinity stays within the suggested range of 80-120 120ppm because if it exceeds 120 ppm, your pH will undoubtedly rise.

What is the difference between pH and Alkalinity?

The distinction between pH and alkalinity is often misunderstood by pool owners. This isn’t surprising, given how tightly pH and alkalinity are linked and affect one another.

The pH scale is used to determine how acidic or alkaline a substance is. It’s no surprise that people misunderstand the terms “alkaline” and “alkalinity.”

On the other hand, knowing the difference between pH and alkalinity is critical to the health of your pool. As a result, pH is used to determine how acidic or basic a chemical is.

It is graded on a scale of one to fourteen, with completely pure water sitting in the center at 7. A solution becomes increasingly basic as the pH approaches 14. The solution becomes increasingly acidic as the number approaches zero.

A pool’s pH should be between 7.2 and 7.4. Because it is as close as possible to the pH of the human body, this somewhat basic pH level is ideal. Pool water has a pH of 7.2-7.4, which is safe for delicate human organs like the eyes, skin, and mucous membranes.

On the other hand, alkalinity is measured in parts per million (ppm). That is, total alkalinity is an absolute measure of all alkaline compounds in a solution.

Carbonate, bicarbonate, and hydroxides are the most prevalent alkaline chemicals found in swimming pool water because of their effect on pH. Certain alkaline substances are significant.

They act as buffers, preventing pH fluctuations. This is accomplished by neutralizing acids. To put it another way, total alkalinity is a measurement of how well your pool water can withstand fluctuations in pH.

Keeping your pool’s water balanced is one of the most common pool maintenance duties. This usually entails maintaining effective chlorine levels and pH balance.

Total alkalinity, on the other hand, is also important for keeping your pool water balanced.


High alkalinity pool water not only affects the pool filter, pool equipment, and plumbing, but it also causes the water to haze and form scale deposits on the pool’s edge.

It also has a significant impact on swimmers, causing skin irritation and itching, as well as eye irritation. Swimming in a pool with high alkalinity may not harm both the pool and the swimmer if the pH level remains within the normal range.

But situations like this arise because even small increases in alkalinity above the normal range have a significant impact on the pH of the pool water, making it unsafe for both the pool’s equipment and the swimmer.

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