JC Pool Services

Pool Water Chemistry 

 Why Correct Pool Water Balance is Important    


Correctly balanced water means the chemical demands have been met, however, if chemical levels are too low the water will aggressively seek the elements it needs by attacking the pool's lining / surface and equipment. This can lead to severe corrosion problems if not corrected. Not only that, improperly treated or untreated water can be a serious health threat to bathers. On the other hand, high chemical levels may lead to the formation of scale on the pool surface and accessories and premature destruction of equipment. 

Incorrectly balanced water can cause expensive damage and inhibit the sanitising process. In simple terms, pool owners should balance the following variables:


  •  pH - Potential Hydrogen
  • TA - Total Alkalinity 
  • Calcium Hardness
  • Stabiliser 


pH is a measure of how acidic or alkaline the water is. The pH scale ranges from 0 to 14, with 7.0 being neutral. Values below 7.0 are acidic, and value above 7.0 is alkaline.  Australian standard 3633 define the range as 7.0 to 7.8 and the recommended range of 7.2 to 7.6 ( or 7.0 to 7.6 for fibreglass pools). Incorrect pH levels can have to following effects;

  • Cause swimmer discomfort - Particularly irritation to the eyes
  • Interference with the action of your pool sanitiser
  • Promote water cloudiness & scale formation

It is important to note that a saltwater chlorinator slowly raises the Ph of the water; meaning acid will need to be added regularly to keep pH in range.

Total Alkalinity (TA), is the measure of Alkaline salts bi-carbonates, carbonates and hydroxides in your water. The Australian standard 3633 recommends a range of between 60 to 200ppm.  Always ask your pool builder or pool shop for advice on the correct level for your type of pool. Low TA can lead to erosion of the surface of concrete or painted pools. For people swimming in water with low TA, the water can feel unpleasant causing mild skin irritation and itchiness. It will also cause unstable Ph levels with small additions of other chemicals resulting in major shifts in pH. This is sometimes known as “pH bounce”. Total Alkalinity can be changed in the following ways;

  • Topping up your pool will change the Total Alkalinity depending on the TA of the Top-up Water
  • Adding Buffer (bi-carb soda) RAISES the Total Alkalinity
  • Adding acid to your pool to lower pH will also LOWER Total Alkalinity


Calcium Hardness is the measure of dissolved calcium in your pool water. The recommend range is 80 to 500ppm according to Australian standard 3633.  Total Alkalinity and Calcium Hardness need to be brought into balance. If the correct balance is not maintained, low levels of CH causes corrosion to the pool surfaces and equipment.  High levels will lead to scale formation. If you are using calcium hypochlorite (granular chlorine) to sanitise your pool, this will raise calcium hardness levels, which will require more frequent testing and adjustment.


Chlorine stabiliser (isocyanuric acid) should be added to the pool and maintained at approx 30-60ppm to reduce chlorine loss due to UV rays. If the stabiliser level is too low, rapid depletion of free chlorine will occur.  If you are using Stabilsed granular chlorine products such as (Sodium Dichlor or Trichlor tablets)  to sanitise your pool, this will raise stabiliser levels, which will require more frequent testing and monitoring.


JC Pool Services are a Focus Products & Chemicals authorised dealer. For more information on the Focus range of chemicals - Click Here