How to balance the pool’s pH level

To keep your swimming pool sparkling and clean, you need to understand pool water chemistry. One important aspect to this is ensuring that the water’s pH level is balanced at all times.

So what is pH?

pH is a measure of how basic or acidic water is.

Why is this important?

Simply put, pool water that is either too acidic or basic causes problems. Water that is too acidic (low pH) causes etching on the pool’s surface which encourages algae growth, metals corrode, more chlorine is needed, and people who swim on the pool get a burning sensation on the eyes and nose and their swimwear fade. Meanwhile, water that is too basic (high pH) results to cloudy water, scaling, and skin irritation.

What is the ideal pH?

The neutral level is pH 7. Anything that falls below 7 is considered acidic and anything that goes above 7 is basic. Most experts recommend a pool pH level of between 7.2 and 7.8.

What causes low pH?

  • Your water source potentially has low pH to begin with
  • You may have used too much pH reducers
  • Rain or ground water
  • Organic materials on the pool

How do you raise the pH level?

With pool water, it’s always a balancing act as the pH level changes. Now if your pool pH testing kit indicates that the water is acidic, you can raise the pH level by using sodium carbonate based products. These products are otherwise known as soda ash.

Add soda ash at the deep end of the pool. When doing this, make sure your pump is running. Test your pool water again after 2-3 days. If the pH level is still low, you can add more soda ash to the water.

What causes high pH?

  • Too much carbonates
  • Too much Calcium Hypochlorite

How do you lower the pH level?

To bring the pH level down, you need to add hydrochloric acid. It comes in all sizes and packages and normally with names like “pH Reducer” or “pH Minus”. When using these products, you need to be very careful as contact to skin causes burn. Read manufacturer’s instructions and wear proper protective gear such as gloves, goggles, and thick long sleeve shirts.

How often do you check the pH level?

Check the pH level of your pool every time you check the chlorine levels. Every time you do it, make sure your pool water stays on the sweet spot between pH 7.2 and 7.8.

The table below shows the recommended method for adjusting the pH of your pool water.

pH Reading Action(s) Required

7.2 to 7.8

  • Ideal Range
  • No action required

>7.8

  • pH needs to be decreased using hydrochloric acid
  • As a general rule, add not more than 1L hydrochloric acid to every 50,000L pool water
  • DO NOT add more acid than is necessary
  • After adding acid as per above, re-test again in 2 to 3 days
  • Do not chase small variations in pH

<7.2

  • pH needs to be increased using Sodium Carbonate (Soda Ash)
  • Add Sodium Carbonate as per the chemical manufacturers recommendation found on the label
  • After adding Sodium Carbonate, re-test again in 2 to 3 days
  • Do not chase small variations in pH

Still need help with your pool chemistry? We have authorised dealers around Australia who can come to you and provide you with expert advice and quality service.