Water test strips for testing pH

Incredibly Important Facts About pH

Protecting swimmers and their families from recreational water illnesses is the reason that pool staff regularly check both chlorine and pH levels. According to the CDC, chlorine and pH are your disinfection team and are the first defenses against germs that can make any swimmer, sick.

What Role does pH Play?

The pH levels in your pool determine the germ-killing strength of chlorine present in your pool. As the pH levels go lower, the chlorine’s power to kill germs becomes stronger. A balanced pH level also helps ensure that any swimmer does not begin to feel skin or eye irritation. A human body typically has a pH balance between 7.2 and 7.8, so once the pool water strays away from this general area, the irritation begins.

How is pH measured?

It’s measured on a scale from 0 to 14, with 0 being the most acidic, 7 being neutral and 14 being alkaline. The pH level must be maintained in a narrow window, between 7.2 and 7.8, for it to be considered balanced.

What Affects Pool Water pH?

The pH of pool water can be affected by a host of factors but the most influential are the type of chlorine used, the pH of the fill water and the pH of rainfall. Chlorine sources can be acidic, alkaline or neutral, depending on type (e.g. trichlor, dichlor, liquid chlorine, salt chlorinators, etc.) Also, depending on where you live in the country, your source water as well as your rainwater can have varying pH levels. For example, in the Northeast US, it is common for the rainfall to be acidic due to industrial gases in the atmosphere.

High pH

High pH decreases the effectiveness of chlorine and the water becomes alkaline which creates the perfect environment for mineral deposits (scale) to form. This then makes chlorine an ineffective agent at killing bacteria and algae.

High pH in swimming pools may cause:

• dry, itchy skin and scalp
• calcium buildup on pool surfaces, waterline and accessories
• clogging of filter medium or elements
• dull or cloudy pool water
• burning eyes and nose

Low pH

Often, low pH is a result of acid rain and typically occurs after periods of heavy precipitation. When pH is low, the water becomes acidic or corrosive and can negatively impact your pool equipment. The secret to controlling pH lies in controlling the alkalinity. Typically, alkalinity levels must remain in between 80ppm to 120ppm.

Low pH in swimming pools may cause:

• eroding of the pool plaster or grouting
• corroding of the metal pool accessories
o i.e. Pool Steps
• staining resulting from metal corrosion
• burning eyes and nose
• dry, itchy skin and scalp
• wearing of swimwear and accessories
What else can be done to promote Healthy Swimming?
According to the CDC, the best way to kill germs is by routinely measuring and adjusting both chlorine and pH levels. Since a few germs can survive for long periods of time in even the best maintained pools, it is also important that swimmers become aware of Healthy Swimming behaviors.

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