What Causes High pH In Pool?

High pH in a pool comes with very severe effects and you need to know the causes to be able to tackle the problem. It’s one of the pool maintenance issues you need to avoid as it can also affect your health.

The major causes of high pH in a pool are:

  • carbon dioxide loss
  • having algae in your pool
  • the sanitizers used in the pool
  • the alkalinity and PH adjustment chemicals used in the pool
  • the introduction of rainwater

Swimming in a pool for about 45 minutes daily is one physical activity that is healthy for the body. It helps to keep the heart rate up. Build endurance and cardiovascular fitness. It even helps you maintain a good weight.

This is why you need to also maintain the pool so you can continue to enjoy these health benefits. One of the things that will thwart these positive impacts is the high ph level of your pool water.

Swimming in a pool with high pH is detrimental to the health of the swimmer. Even the pool components will be affected as well. So it is of utmost importance to always avoid a high pH level in your pool water.

But how will you deal with it without knowing the possible causes? This is why this piece is here. It will help educate you on the causes, and of course, the best solutions as well. Knowing the potential causes of high pH levels in a pool will help you to handle your pool pH level better.

What is high pH in a pool?

High pH in a pool is when the pH level exceeds the normal 7.8 level. It shows that the water in your pool has turned alkaline and swimming in it will come with consequences. Once the water pH level gets to 8.0 and upward, the water pH is very high.

The right pH level for your pool

PH level is measured on a scale of 0-14 with 7 being neutral. So, the pH value is between 0 and 7 which is considered acidic, and the value from 8-14 is alkaline. So the ideal level is between 7 and 8. This simply means that the right pH level for your pool would be between 7.2 and 7.8, you can find this out by using your test strip to test your pool water.

What happens if pH is too high in a pool?

As long as you have enough money, owning a swimming pool might be an easy thing. But caring for it effectively is the difficult part. Apart from treating the pool, adjusting the chemicals and the pH levels of the pool needs to be dealt with. One frequent problem you would always encounter with your swimming pool is the high pH level. Once the pH level in your pool becomes high you would experience the following;

  • The water becomes alkaline: The pool water will no longer be fresh and clean because of the alkalinity level. Swimming in such pool water may cause irritation and itchy skin.
  • It reduces the effectiveness of the chlorine: The main chemical that is responsible for killing pathogens and other contaminants in the water will be weakened. This leaves the pool unrestricted to bacteria infiltration. With this, a swimmer can get easily get infected after using the pool.
  • You experience skin rashes: High pH water will have contaminants in it as earlier stated. This will make the water unfit for use. If the owner uses the pool in such a bad state, it may cause itchiness on the body, and this will result in pool rashes called swimmer’s itch.
  • The water becomes cloudy: If the pH of the water becomes high, the sanitizer, which is usually chlorine-based, will become ineffective. The contaminants in the water will grow since the sanitizer is no longer active. If the situation is not properly handled as soon as possible, the organisms will multiply. This will make the water cloudy and unfit for use.
  • Scaling on pool equipment: From our discussion so far, we know that a high pH level increases the alkalinity of water. High alkalinity makes water hard. This hardness brings about scale formation due to calcium deposits. The scale buildup may then clog the pipes and filters. In some cases, it will make the pool equipment leak and have a motor failure.
  • Restriction of water flow: This is another problem that you would be confronted with when your pool water pH is high. It is more like a chain reaction. Of course, when there’s a scaling of the pool’s components, the scaling inside pipes will buildup over time. This will lead to a blockage from all the debris and the result will be restriction of water flow.
  • Putting a strain on the pool circulation system: All the debris that will come from the scaling of the pool’s equipment which is due to high pH will strain the circulation system. It will make it less effective and you would need to repair it. So it will either be a repair or a replacement – either way, you would be spending a high amount. You can avoid these extra expenses by ensuring that the pool pH is within the ideal range.

Causes of high pH in a pool

To know whether your pH level in your pool is high or not, you need to test the water. If the test shows anything close to 8 and above, you should know that the pool pH level is high. The resultant effect will be the water becoming soft and unsafe for use.

Once that happens, you need to do your best to know what is responsible for the increase in pH level. Knowing the possible cause will help you to prevent it from happening in the future. It will also help you to tackle the issue properly.

Below are some potential causes that might have set your pool water pH high.

  • Algae presence in your pool: The algae you have in your pool consume carbon dioxide. Of course, this process of consumption will deplete the carbon dioxide in the water. This depletion of CO2 will result in a high pH level in the pool. If it continues for a long period, the pH level may go above 8.0 and that makes the pool excessively harmful to users.
  • Loss of carbon dioxide: What happens here is the dissolving of carbon dioxide in water. So when this occurs an acid known as carbonic acid is formed. The presence of this acid in the pool will further lower the pH level of the water. Moreover, with the splashing of water, carbon dioxide can be lost.
  • Introduction of rainwater into the pool: Rainwater creeping into the swimming pool can also make the pH of the pool high. It raises the pH of the water via dilution. The impact will be on the pool water chemistry and even the alkalinity levels. The bottom line is that rainwater that falls directly into the pool, whether an outdoor pool or not, will dilute the water, and the effect will be an increased pH level.
  • The rise in temperature: Another outstanding issue that causes the rise of the pH level in the pool is an increased temperature. The thing is that once the temperature of the water increases, the pH level will increase. This is caused mostly by direct contact of the sun to the pool. The unexpected heatwave does the same to the pool. So you need to watch the temperature of your pool because the rise may affect the pH level.
  • The sanitizers and shocks used in the pool: You need to be wary of the kind of chemicals you apply to your pool water. It is on record that chemicals used to sanitize the pool can affect the pH of the pool water. Some of these chemicals have high pH in them. When you apply them to your pool it also raises the pH level. So, try and test for pH levels anytime you use them.

How to prevent having a high pH level in your pool?

Different factors cause high pH in the pool as outlined above. But you can stop your pool from experiencing incessant high pH levels. Considering the below workable tips will be helpful.

  • Cover your pool when not in use to avoid direct exposure to the sun or rainwater.
  • Fight the algae present in your pool with a good algaecide.
  • Use the right sanitizer and the right amount for your pool capacity. This will help kill all the organisms in the water leaving your pool clean and fresh.
  • Test your pool water on the regular and treat it immediately it exceeds 7.8.
  • Don’t allow your pool water to turn cloudy and don’t use your pool in such a condition. The water is contaminated already.
  • Don’t use detergent or soap to wash your swim pants. You can use vinegar but rinse very well with clean water.
  • If possible, avoid the use of calcium in your swimming to avoid a build-up.
  • Call in an expert once in a while to help you out when needs arise.

How to lower the pH level in your pool

When you discover that the pH level in your pool is high. The best solution is to lower it to the recommended range which is between 7.2 and 7.8. High pH in a pool comes with its consequences, so avoid getting into more trouble. To achieve this, you can use these two methods to lower the pH level:

  • The use of sodium bisulfate products
  • The use of muriatic products

The products that come with these chemicals are termed pH reducers or pH minus. So whenever you are buying pH-reducing products make sure they contain any of these two chemicals.

Method 1: The use of sodium bisulfate products

This is a pH reducer that contains sodium bisulfate and comes in powder form. Note: Don’t use it on a windy day because they come in powder form. The good thing about this chemical is that it can easily be stored and it’s a lot safer to use. It is milder than the muriatic acid but very effective in reducing pool pH levels.

Steps to use

  • Test the pH of your pool: You need to be sure that your pool pH is high. So use your test strips to find out.
  • Next, measure the chemicals according to the manufacturer’s guide. You can start with at least ¾ of the recommended dose, and then keep adding more from there if need be.
  • Then, add the powder straight into the return jet sites. This is to make sure it is entering where the water enters from. Avoid adding it via the skimmer.
  • Allow for about 15 minutes, let the filtration system circulate the chemical.
  • Retest the water: You would need to retest the water within 24 hours. If it is at the ideal range then you are done, but if not, you would need to repeat the process.

Method 2: The use of muriatic acid products

The muriatic acid products can also help in reducing the pH level of the pool. So you can get one of your choices, they come in liquid form. It is one chemical that you need to use with caution. It’s a powerful chemical.

Steps to use

  • As usual, you test the water to know the pH level of the pool water.
  • Measure your chemicals, and stick to the manufacturer’s instructions.
  • Add the chemical. You can either turn off the pump and pour in the chemical at the deep end of the water. You can also pour it via the return jets.
  • Allow the chemical to dissolve for some hours.
  • Then retest the water within 4 hours but if still high you can repeat the process.


There are numerous causes of high pH in a pool as outlined in this article. The best you can do for your pool is optimum maintenance. Once you make that your priority, your pool will always be ready to serve you well. So stay on top of your game by keeping your pool clean. Shock it when necessary, and clean the filtration system regularly.

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