pH stands for Potential of Hydrogen and is a measure of the acidity of a solution, in our case pool water.

The pH is a measure of the Acid level in a pool. On a scale of 1 to 14 it goes from Acidic (1) to Basic (14). A pH of 7 is for neutral water. The recommended Ph for a swimming pool or spa is 7.2 to 7.6. This is controlled by adding acid to lower the pH or Soda Ash to raise it. Buffer actually raises the alkalinity but as a by-product it will also raise the pH.

Concrete, pebblecrete, marblesheen and concrete pools have a tendency to be too basic and require acid regularly. Fibreglass and vinyl pools will have a tendency to be too acidic and may require soda ash occasionally. This is due to the surface of the pool. For more information see Alkalinity.

An incorrect pH in heated pools or spas can lead to corrosion of heater elements, seriously shortening their life expectancy. This is why we now recommend Nature 2 (pH neutral) instead of Bromine (acidic/corrosive) in spas.

If your pH gets too low, the water becomes acidic and this can result in swimmers getting sore eyes.

If your pH gets too high it allows algal growth and does not let the chlorine sanitise the water properly.

Hydrochloric Acid is the chemical term for the acid used however when in this weaker form it is also called Muriatic acid. Various brands have labelled it as pool acid, ph down and ph decreaser.