What Happens When Pool pH Is Too Low?

An essential part of having a pristine and safe swimming pool is keeping the pH level of the water at optimal levels at all times. The pH level measures the acidity or alkalinity of the water, and it has an important impact on the safety and health of swimmers. When pH levels are too low, your pool can potentially be unsafe to use. 

What problems are associated with low pH levels, and how long does it take to raise pH in a pool? In this article, we will examine these questions and address ways to deal with low pH issues in your pool.

What is pH in Swimming Pool Water?

The pH level in a pool indicates the concentration of hydrogen ions in the water. The pH scale ranges from zero to fourteen, with a pH of seven being neutral. If the pH is lower than seven, the water is considered acidic, and if the pH is higher than seven, the water is considered alkaline.

The ideal pH level for a swimming pool is between 7.2 and 7.8. Keeping the pH within this range ensures that the chlorine can do its job of safely disinfecting the water and ensuring safe conditions for users. Low pH levels will cause the chlorine to evaporate.

Factors That Can Cause Low pH

Let’s take a look at what causes low pH levels in swimming pools:


Heavy rainfall can cause pH levels in a pool to drop, especially in areas with acidic rain. If your pool isn’t covered and rain infiltrates the pool water, you’ll likely notice your pH levels begin to decrease over time.


The addition of pool chemicals like stabilizers, shock treatments, and algaecides can lower the pH level in a pool.

Carbon Dioxide

Carbon dioxide, or CO2, can enter a pool through rain, algae, or swimmers’ exhalations. When CO2 levels increase, they can cause the pH level to drop.


Swimmers often bring contaminants, such as sweat, urine, and body oils, into a pool, which can lower the pH level. When there is a high volume of pool users, pH levels can drop significantly in a relatively short time period.

Acidic Sanitizers

Some swimming pool sanitizers, such as bromine, are acidic and can lower the pH level when used in excessively high quantities.

Negative Effects of Low pH in a Pool

Irritation and Discomfort

Low pH levels can irritate the skin, causing itching, rashes, and redness. Stinging, burning and redness can also occur in the eyes of users when a pool’s pH is too low.


Low pH levels can corrode and damage pool equipment, including pumps, heaters, and filters, shortening their lifespan and leading to high repair and replacement costs.


Low pH levels can lead to the growth of algae, making the pool water cloudy and unpleasant.

How to Increase pH

Sodium Carbonate

Also known as ‘soda ash,’ sodium bicarbonate is an alkaline substance that raises pH levels. Soda ash is applied by dissolving it with the pool water. Generally speaking, six ounces of soda ash added to a 10,000-gallon pool will increase the pH level by 0.2.

Baking Soda

Baking soda, or sodium bicarbonate, can be used by adding approximately 1.5 pounds of baking soda per 10,000 gallons of water and distributing it evenly over the pool surface while the filter is running.


Borax is a natural mineral, and it is used by dissolving 1.5 pounds worth per 10,000 gallons of water, evenly distributed throughout the pool water.

A pH increaser

A pH increaser is a commercial chemical designed to raise pH levels. It is considered to be stronger and more efficient than baking soda, and can have rapid effects without having to use large quantities.

Wrapping Up

If you are looking to have a safe, well maintained, and inviting pool, you’ll want to avoid low pH levels. Regularly check your levels, and, should they drop, follow the courses of action detailed in this article to get them back on track!

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