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The ‘old salt’

04 April 2012 swimart

The ‘old salt’

The 'old salt'

Australia leads the charge with salt water pools

They've been around since the 1980s, but it wasn't until the early 'noughties' that salt water pools really began to take off and pool owners began to recognise the benefits.

Put simply, salt water chlorinators create chlorine which keeps the pool sanitised. And Australia leads the world in this type of automatic chlorination. In fact, it's estimated that approximately 80 per cent of all new in-ground pools built in Australia each year will have a salt chlorinator installed as standard equipment.

In the 2012 Summer Pool Owner's Survey, salt was by far the most popular type, with 69 per cent of existing pool owners admitting they have salt pools, with just 31 per cent having chlorine pools.

 

How the salt water chlorinator works
A chlorine generator's main function is to produce chlorine for the pool so you do not have to buy it, store it or handle it. Through the process of electrolysis, water passing over the chlorine generator cell produces chlorine that is instantaneously transformed into hypochlorous acid, which is the sanitising agent that kills algae and other harmful organisms in the water. As such, a saltwater pool is not actually chlorine-free; it simply utilises a chlorine generator instead of the direct addition of chlorine.

Why salt water?
Ocean water has a salt content of around 35,000 parts per million (ppm). Humans have a salt taste threshold of around 3,500 ppm. Most chlorine generators require a salt content of 2500 - 6000 ppm in the pool, and units requiring 3000-5000ppm are ideal.

Swimming in a mild saline solution is much like taking a shower in soft water. In a salt water pool (one with a chlorine generator), the water feels smooth, your skin feels smooth and many people feel more refreshed.

Conditioning the pool water
The hardness in the water can cause scales to build-up, particularly where the pH is high (such as in a salt chlorinator), or where the water temperature is high (such as in the surface of heat exchange elements of a gas or electric heater).

The use of a water conditioner does not stop the formation of scale, but rather prevents it from forming a hard shell over these surfaces. The water flow in the plumbing will help to disperse future scale formations, minimising problems during the routine maintenance.

Cleaning the salt cells
The salt chlorinator's cell should be visually examined once per season, or if you think there might be a problem. The cell should be clear of debris and the plates should appear either black or metallic.

The secret is keeping the cell free of calcium and mineral deposits. The cell itself is made up of rare metals which must be maintained so it can continue to make chlorine. To be effective, it is vital to maintain proper water balance, i.e. pool chemistry and pH.

If some of the plates have a white crusty or flaky buildup, the cell should be cleaned according to the directions that came with your salt chlorinator. Cleaning typically involves soaking the cell in a dilute muriatic acid solution. A white buildup on the cell plates, or thin white flakes of calcium getting into the pool, indicate a water balance problem which needs to be corrected to avoid ongoing problems.

Salt level
Not only will the chlorine production be affected by a low or high salt level in the pool, but also the life span and efficiency of the salt cell. This level varies depending of your salt chlorinator model.

Swimart pool technicians can advise on the correct salt level according to your salt water chlorinator type. Testing kits are available and should be used to accurately check the salt levels in the pool water.

What products to use for protecting your salt cell chlorinator
Swimart stocks the Aqua-Health range, which includes the following suitable products:

  • Aqua-Health Salt chlorinator Water Conditioner
  • Aqua-Health DeCal Cell Wash - (Electrode Cleaner)

Effect of water chemistry

If the water chemistry of the pool is unbalanced, calcium buildup might occur over the cell plates, affecting the longevity and efficiency of your salt chlorinator. Most salt water chlorinators operate between the following ranges:

Parameter Typical Values Suggested Work Range
pH: 7.2 - 7.8 7.2 -7.6
Total alkalinity: 60-200 ppm 80-150 ppm
Calcium hardness: 100-500 ppm 60-250 ppm
Stabiliser: 30-60 ppm

Consult your local Swimart technician for the correct water balance parameters according to your pool type.