What Happens If pH Is Too High in Pool?

There is no remedy for sweltering hot summer days quite like a refreshing dip in the pool. However, most of the time, you probably dive right into the chemically-infused water without inspecting the pH levels. If you are swimming in a pool with a high pH balance, you could be posing a potential threat to both your body and pool.

When pH is too high (above 7.8) it becomes too alkaline, and this decreases the effectiveness of chlorine to keep the water clean and free of bacteria. If this happens then problems such as skin rashes, scaling on pool equipment, algae growth and cloudy water can occur if high pH levels are left untreated. Recommended pH levels are between 7.3 and 7.6 to maintain clean and safe water.

Luckily, you can take precautionary methods and solutions to prevent high levels of pH in your pool’s system. How do you get started? Read on to learn all about what happens if your pool’s pH gets too high and how to maintain your pool’s pH properly.

What Happens If pH Is Too High in Pools?
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What can happen if the pool’s PH is too high?

As stated above, the higher the pH, the more alkaline or basic a pool’s water is. High alkaline water can affect not only your body while you swim but also your pool system as well. Both our bodies and our pools work to operate on a delicate pH system. Once that system gets off balance, the effects are negative and immediate.

Some effects on the body include:

  • Skin rashes
  • Red eyes
  • Dry skin

Then, there are the effects on the pool system:

  • Cloudy water
  • Scaling on pool equipment
  • Aging of pool liner
  • Clogged filters

These are the consequences of elevated pH levels and should be accounted for when adding various supplements to your pool water. It is important to check your pool’s pH balance regularly to avoid harm to yourself and your pool system.

Is it safe to swim with high pH?

Now that you understand the risks that tie along with high pH levels, the question that remains is whether or not it is safe to swim. 

Experts suggest steering clear of water with a pH over 7.6 due to the damage it could cause to the body. If the water is leaning on the alkaline side, this raises the potential for chlorine, a bacteria destroyer, to stop performing its job. Bacteria and algae growth can be harmful to the body when it enters one’s system.

Physical effects can be seen as well.

  • Skin irritations (rashes, burns)
  • Dissolving skin and hair oils (dryness, itchiness)
  • Swollen eyes (redness, burning)

These effects can be very uncomfortable. Overall, it is best to avoid swimming in your pool until you are able to lower the pH to a safe level. 

What causes high pH in pools?

The most common reasons why you may have high pH are:

  • Too much chlorine
    Adding granular chlorine can have the effect of raising pH when shocking the pool
  • Too much pH plus chemical added
    If your pool pH levels are low then the solution is to add pH plus chemicals to raise it but it is possible overdo this and ed up with high pH.
  • Algae
    If algae is be present it consumes CO2 and that in turn increases pH levels

How to lower pH levels

While your high pH levels might be causing you grief, you can fix them quite easily.

Muriatic acid and sodium bisulfate are most often used chemicals to reduce the pH levels in a pool. Both are known as pH reducers designed for swimming pools and are extremely effective.

Muriatic acid

Muriatic acid is very powerful as it is a diluted version of hydrochloric acid. The substance comes in a liquid form, so you should take precautions when handling it.

Steps to add muriatic acid to your pool:

  • Test your pool’s chemical levels with a liquid or strip pool testing kit.
  • Wear protective gear that comes to your arms and legs to avoid acid burns on the skin, as well as goggles to prevent droplets in the eyes.
  • Dilute the acid before dumping it into the water to allow the right chemistry to be reached. Always dilute it by filling a bucket with water first and then add the chemical – never add the chemical first. Don’t pour the acid directly into the water without diluting it first as it could cause a harmful, chemical reaction.
  • Walk around the pool slowly pouring in the diluted acid to distribute it evenly.
  • Leave your pool pump running to circulate the water.

Once you have completed the process, allow a few hours for everything to mix properly, then check the pH levels. If the pH is still high then add some more muriatic acid.

Do not allow access to the pool until the levels are safe.

You can purchase Muriatic acid on Amazon – Acid Blue Muriatic Acid

Acid Blue Muriatic Acid

Sodium bisulfate

Sodium bisulfate is easier to add and safer to handle than muriatic acid. It comes in a dry form but should still be handled with caution.

Steps to add sodium bisulfate to your pool:

  • Test your pool’s chemical levels with a liquid or strip pool testing kit.
  • Depending on the pH level and how much is needed to reduce it, some experts recommend ¾ of what the instructions call for. You can always add extra later.
  • Read the label to determine whether the product needs to be diluted.
  • Walk around the pool slowly pouring in the sodium bisulpahte to distribute it evenly.
  • Leave your pool pump running to circulate the water.
  • After the water rests for six hours, retest and add more if necessary.

Remember, it is important to follow the specific guidelines and procedures labeled on the chemical’s container before adding either of these chemicals to your pool.

You can buy sodium bisulfate on Amazon – Pool and Spa pH Reducer

Pol and spa pH reducer - sodium bisulfate

Ways to prevent high pH

High pH levels in your pool can be avoidable by staying vigilant. Keeping a stable pH comes down to measuring it regularly, perhaps even daily, to maintain consistency. This way, you can catch problems in advance before they become too much of an issue.

Your levels may lean toward the low or high end of the spectrum. Since you have already learned about high pH, here are suggestions on how to tackle low pH levels.


Summertime calls for pool parties and family cookouts, making clean and safe water essential. When pH levels exceed a measurement of 7.6, there is too much alkaline in the water, which can cause physical trauma to someone or damage expensive pool equipment.

Swimming in a pool with high pH is not recommended. The amount of alkaline can cause skin rashes, swollen eyes, and irritation to the scalp. Large amounts of alkaline can also reduce the effectiveness of chlorine, promoting bacterial and algae growth. While these issues can be troubling, there are solutions and prevention methods to balance out pH levels and restore the chemical base.

If you have the opposite problem then you will find help here How to raise the pH in a pool

Pool Maintenance Course

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It was probably the best money I spent that year as I have saved thousands by doing it myself.