The Importance of Correct Water Balance

Improperly treated or untreated water can be a serious health threat. Correctly balanced water means the chemical demands have been met. If chemical levels are too low the water will aggressively seek the elements it needs by attacking the pool lining and equipment. This can lead to severe corrosion problems.  On the other hand, high chemical levels may lead to the formation of scale on the pool surface and accessories.  Incorrectly balanced water can cause expensive damage and inhibit the sanitising process.

In simple terms, a pool owner should balance the following variables:

• pH
• TOTAL ALKALINITY
• CALCIUM HARDNESS

pH

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 (7.0 to 7.6 for fibreglass pools). Incorrect pH levels can have to following effects;

• Cause swimmer discomfort
• Interfere with the action of your pool sanitiser

It is important to note that a saltwater chlorinator may raise the Ph of the water; this means acid will need to be added regularly.
 
Total Alkalinity (TA)

Total Alkalinity (TA), is the measure of bi-carbonates, carbonates and hydroxides in your water. The Australian standard 3633 recommends a range of 60 to 200ppm.  Always ask your pool builder or pool shop for advice on the correct level for your type of pool. Low TA will lead to erosion of the surface of concrete and painted pools. It will also cause unstable Ph levels with small additions of 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

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 cause corrosion to the pool 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.

Stabiliser

Chlorine stabiliser (isocyanuric acid) should be added to the pool and maintained at approx 30-50ppm to reduce chlorine loss due to UV rays. If the stabiliser level is too low, rapid depletion of free chlorine will occur, if too high it will “lock up” the free chlorine residual.

Algae Problems

Algae is the name used to describe simple organisms that are similar to plants (have the ability to photosynthesise) and are commonly found living in water. In swimming pools, algae growth often resembles moss. These tiny little microscopic organisms feed on nutrients contained in the water. Algae produce spores that may already be present in the water; be transported to the pool by wind or attached to other debris.  Algae require only air, sunlight, water and a good supply of nutrients to flourish. They are usually found in shallow waters and areas around steps and swim outs. The simple way of combating algal problems is by “shock dosing” the pool with chlorine and adding a good quality algaecide (usually a mixture of complex copper salts). This process will overcome the problem by starving the algae of nutrients, causing them to die. Once the algae are dead, the residue will need to be removed by filtering or vacuuming out, leaving the pool crystal clear. 

Ionisers

Ionisers are an alternative means of pool water sanitisation by using silver or silver and copper ions that are built into the pool filtration or circulation systems. The Australian authority for Public Health in relation to pool sanitisers, (The Australian Pesticide and Veterinary Medicines Authority) is not confident that pool and spa sanitising systems based solely on silver or silver and copper are adequate in controlling harmful bacteria. The bacteria that are not controlled by such devices can potentially cause serious health problems. Ionisers should be used in conjunction with other, APVMA registered, pool chemicals to ensure a safe pool or spa environment.

For further information go to: www.apvma.gov.au