Water Balance



  previe1Maintaining your pool water in the proper balance bays big rewards.  First, water that has its key chemical factors in the appropriate balance range makes for very comfortable swimming.  Second, balanced water makes pools easier to maintain.  Properly balanced swimming pool water meets the following criteria:

  • pH: 7.2 – 7.8
  • Metals: none
  • Total Alkalinity: 80 -150 ppm.
  • Calcium Hardness:     180 -250 ppm (vinyl pools)     200 -275 ppm (plaster pools)
  • Total Dissolved Solids: less than 1,500 ppm.

Use your test strips to check your water’s pH and alkalinity once a week, or after any major change (such as when you add a large amount of new water, or after a long, heavy rain).


The amount of alkalinity in your water can affect swimmers’ comfort.  High alkalinity will push the pH reading upward, while low alkalinity can promote pool corrosion and cause “pH bounce”, which is a large change in the pH reading after you add adjustment chemicals.  The ideal total alkalinity range is 80-150 ppm.  Always test and adjust the total alkalinity level before adjusting the pH.


pH is a measure of the acidity or basicity of the water and is measured on a scale ranging from 0-14.  Swimming pool water should have just a little basicity with a pH reading between 7.2 and 7.8.

If pool water is too basic, scale can develop– particularly in hard water areas.  If it is too acidic, the water can become corrosive.


Calcium hardness also affects the balance of your pool water.  Low calcium hardness will promote corrosion.  High calcium hardness can cause cloudiness and scaling.  The ideal calcium hardness content is 200-275 ppm for plaster pools, and 180-250 ppm for all other types.


It is not uncommon to find metals, often called free metals, dissolved in pool water.  Usually they come from source water–sometimes they come as a result of the erosion of metal pool fixtures such
as heater cores.

Free metals in pool water can cause staining of pool surfaces and inhibit the performance of water sanitizers.  Ideally, there should be no metals in the water: 0 ppm.