It's All In The Salt

By Ian Jenkins
Tuesday, 18 December, 2012

It's All In The Salt

Different products impact pool water differently and finding the right combination of quality products is the key to maintaining a healthy pool. Salt is the primary ingredient in keeping saltwater pools healthy and operating effectively, but it’s not as simple as adding any type of salt to your clients’ pool water.

Salt is required for electrolysis to take place in the electrolytic chlorine generator (salt chlorinator) to produce chlorine that sanitises the water. The right amount of salt allows the salt chlorinator to produce enough chlorine to help keep the pool healthy and fight algae and other bacteria. 

Using poor quality salts or putting in incorrect levels of salt into your pool (either too high or too low) can impact this process and damage salt chlorinator equipment. Some of the common problems associated with poor quality pool salt includes staining, scale and increased chlorine demand. Organic contaminants found in pool salts are the number one cause of common water problems like cloudy water or increased chlorine demand. Also, inorganic contaminants usually affect water clarity, dissolution rate and other water health factors. 

What is good quality pool salt?

All salt crystals used for pools contain sodium chloride (NaCl), but it's the level and type of contaminants that are embedded within the salt crystals that determines its quality and this usually depends on where the raw material was originally sourced. In Australia, pool salt is produced in a number of ways including mining and mechanically or naturally evaporating it from salt water lakes.  

One of our major salt suppliers has solar salt fields on coastlines and large inland lakes in Queensland, New South Wales, Victoria and South Australia that rely heavily on a natural evaporative process to create salt. Cheetham Salt pumps seawater into shallow ponds and as the sun and the wind evaporate the water, the solution is slowly guided through a series of ponds and finally into a thick layer of salt on the crystaliser floor. It is then harvested, crushed, washed and screened into specific particle sizes and packaged to suit the needs of the end customer. Because the salt crystals have been crushed and refined, a lot of the impurities (or contaminants) are removed to ensure a high quality product for pool use. 

Identifying good quality pool salts

Sometimes pool salt with contaminants or impurities has characteristics that can be immediately recognised. These include shape and colour of the salt crystals and the impact they have on pool water when added. Below are some tips on how to identify poor quality pool salts.

Finely crushed: pool salts should almost appear like table salt as this means they have been refined to remove impurities. It doesn't always mean the salt is 100 percent pure, but the processing and cleaning of the salt before it is packaged helps to remove contaminants.

Irregular shape: chunky, irregular shaped salt crystals are usually a sign of salt with contaminants and impurities embedded within. Uniform cubic shape salt crystals are purer and make it a better choice for pools.

Labels: professionals in the pool care industry should always use salt specifically produced for pools. Other types of salt can contain additives that affect the efficiency of the chlorinator.  

Colour of the salt: pool salt that is snow white in colour is better quality as it is more refined and purified. Off-white pool salt often indicates impurities and poor quality. 

Water discolouration: if by adding salt the colour of the pool water changes, this is a sign of inorganic contaminants such as metals being present.

Solving common water quality issues

Using poor quality salt in your pool can lead to staining and scaling on your pool surface. It can do the same to the inside of your pool equipment, thus increasing the wear and tear and lessening the lifespan of your equipment. Using a quality pool salt will lower the risk of these problems.  

Calcium scale: scaling can be identified by the visibility of white or grey chalky matter on pool walls, floors or equipment and if chlorine levels become difficult to maintain. It is perhaps the most damaging as it also affects the effectiveness and lifespan of the chlorinator. Scaling can also be hazardous for pool users, especially young children as it can be harsh on skin. Scaling can be treated and removed with diluted muriatric acid and, once it is removed, prevent it returning in the future by maintaining proper water balance. 

Staining: early signs of staining as a result of poor quality pool salts can be identified by minor streaking on pool walls and discolouration of the water. Although it doesn't harm swimmers, scaling detracts from the overall appearance of the pool and ultimately damages it. Stains can usually be treated with products containing citric, absorbic or sulfamic acids. Removing dissolved stain-causing metals from pool salt can usually be accomplished with filter aids. 

Chlorine demand: when the amount of chlorine produced by the chlorinator can't overcome high levels of contaminants in the water, chlorine demand or "cloudy water" occurs. This can be caused by bather load or trees and plants debris and is also often caused when impure pool salt is first added to pool water. Cloudy water can be treated with filter aids and cleaning the pool filter.  

Slow dissolution: the amount of time and brushing needed to completely dissolve salt is an indicator of salt quality. If salt remains on the pool surface too long while it dissolves it may lead to weakening the plaster surface and cause staining and etching, so it's important to make sure that the salt is completely dissolved. Fine salt crystals generally dissolve faster and more effectively. 

Maintaining a healthy saltwater pool

On top of choosing high quality pool salts, there are several other factors that affect the water health of a pool including maintaining the water balance and chemical balance to assist the pool equipment in processing the salt to chlorine and lengthen the lifespan of the equipment. A good quality salt chlorinator will also produce more chlorine for a longer period of time and ultimately have a longer lifespan. 

It is also important to consider appropriate maintenance and treatment products without phosphates or sulphates for salt water pools. Products containing sulphates and phosphates that are not formulated for salt water can cause scaling and early algae formation. Products to look out for are products that contain anti-scale and anti-stain agents which are proven to work in salt water pools. PoolWerx has partnered with industry experts to maintain a high quality product that provide clients with the best treatment for their saltwater pools and guarantees a healthy and long-lasting swimming pool.

Some important points to take into consideration:

  • Quality pool salt is a key factor in keeping saltwater pools healthy.
  • Poor quality salt can produce several problems in a salt water pool including staining, scale and increase in chlorine demand.
  • Pool salt crystals can vary in shape and colour and quality can be immediately identified based on the impact of salt on pool water.
  • Products to look out for are products that contain anti-scale and anti-stain agents, which are proven to work in salt water pools.

Ian Jenkins is Training and Operations Manager at PoolWerx with over 20 years' experience in the pool and spa care industry. 

PoolWerx is Australasia's largest pool and spa care network with over 200 active franchise territories operating more than 300 service vans and 70 retail hubs in Australia and New Zealand. For more information call 1800 009 000 or visit

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