Hard Water

What is Scale or Limescale?

Limescale (or Calcium Scale) is a solid, off-white chalky material frequently seen on the metallic parts of water-operated equipment. It is mostly common in machinery and equipment that contains heating elements (such as boilers) or heat transfer elements (such as heat exchangers).

Limescale can also be seen in metal pipes, pumps, filters and other water equipment to a lesser or greater degree, contingent upon water quality.

The increase of this scale, which occurs over time, can brutally impede the efficiency and dependability of machinery, pipework and processes, ultimately producing a reduction in efficiency and costly breakdowns.

Where does Limescale come from?

Limescale deposits (usually referred to as “scale”) are produced by small amounts of naturally occurring minerals found in most tap water supplies. Under the right circumstances, these minerals form deposits of Calcium Carbonate, Magnesium Hydroxide and Calcium Sulphate to metal surfaces.

When water contains higher concentrations of Calcium Carbonate, Magnesium Hydroxide and Calcium Sulphate it is known as “hard water”.

Hard Water in Australia

The hardness of water varies greatly from region to region in Australia. Measured in parts-per-million the Australian Water Association has discovered ranges of 10ppm to 226ppm across the capital cities.

Commercial Impacts of Limescale

When Limescale builds up inside machinery and water equipment it slowly reduces performance outputs. Because this reduction in performance doesn’t happen all at once but slowly, over a period of time, these changes usually go undetected until it’s too late, concluding in long term losses of efficiency that persevere for long periods.

When Limescale builds up on heat transfer surfaces it acts as an insulator, decreasing the effectiveness of heat transfer. In heating applications this results in increased energy usage and additional loading on heating elements. In cooling equipment there may be a noticeable increase in thermal stress due to ineffectual cooling which can result in a reduction in efficiency and greater failure rates.

If left unchecked, pipes and pumps with Limescale deposits experience diminished water flow as the scale build up constricts critical openings. Over time Limescale can reduce flow in even large diameter pipes to a mere trickle or even block flow entirely.

Hard Water can produce Scale and Limescale build-up in pipes and taps at home

Any tap water comprising higher than normal quantities of minerals (primarily calcium and magnesium) is referred to as hard water. As hard water flows through pipes and fixtures it can leave behind lime and mineral deposits which harden and become almost impossible to remove. We refer to these deposits as scale and Limescale.

Another problem with hard water, in addition to scale and Limescale is the effect it has on cleaners like body wash, soap, dish washing liquid and laundry detergent which do not work as well in hard water. Hard water reduces the effectiveness of these cleaner which means you need to use more in most cleaning applications. It also means a residue sometimes called soap scum or film is left behind on shower screens, bathtubs and on crockery, glass ware and so on.

Here’s a summary list of some of the problems cause by hard water use in your home:

• Decreased lathering of soaps and detergents which results in using more soaps and detergents to get the required result
• Lime scale deposits which build up in pipes and taps and can eventually reduce water flow and damage appliances
• Hard to remove scum lines around baths which are ugly and take a lot of elbow grease to clean
• Plumbing problems such as blocked or corroding pipes
• Increased electricity costs which hits you in the wallet
• Dry itchy skin of eczema irritation

The upshot of hard water however, is that your body needs the minerals for optimum health. So removing the minerals is not necessarily the best option.

Check out our range of Softerwater conditioners to reduce scale and Limescale deposits without removing vital minerals from your drinking water.

Hard Water In The Pool

There are two types of water hardness that can have a negative effect on your swimming pool, pool accessories and the water.

1. Low calcium hardness. The outcome of low calcium hardness is corrosive water. Signs of low calcium harness are:
   
   – Any plaster surfaces or grouting around tiles softens and erodes,
   – Any metal equipment and accessories oxidize and rust leaving a stain on the pool’s surfaces which can ultimately lead to a requirement for resurfacing
   
   
2. High calcium hardness. High calcium hardness produces scale on the pool surface and scaling in the pipes, plumbing and filter. If the calcium hardness levels get too high it can lead to dull and cloudy looking water. This typically is a sign that the calcium content of the water is precipitating out into the water rather than onto a surface. High calcium levels in a swimming pool, in addition to creating scale are a major source of aggravation creating sore eyes.

Water hardness problems don’t need to lead to scale and Limescale formation in your swimming pool. Your swimming pool water hardness problems can be fixed with the simple addition of the right Softerwater conditioner from our range. Call or email our office to discuss an effective solution that’s right for you.

In steam generating equipment the buildup of scale and other materials such as sludge on the surface areas of a boiler can produce overheating and even corrosion. Both corrosion and overheating can result in unscheduled downtime of your equipment.

Typical contaminants found in boiler feed water that form scale or sludge include calcium, magnesium, iron, copper, aluminum, silica, and sometimes even silt and oil. These materials either harden as scale on the boiler tube surfaces or as sludge deposits that form elsewhere in the system and travel to the metal surface by way of the flowing water.

Scale is formed when salts, which have restricted solubility, find their way into the boiler water. When in a soluble form these salts will precipitate when compounded by evaporation. Scales forms because when precipitates form they usually have a homogeneous composition and crystal-like structure.

High evaporation is caused by high heat, which serves to concentrate the unevaporated water in the area of evaporation. The concentrated water creates the perfect environment for the precipitation of scale-forming compounds. The quality of the scale is determined by the composition of the concentrated water. Typical chemical composition of scale includes calcium, magnesium, silica, aluminum, iron, and occasionally sodium.

The hardening of chemicals into scale does not happen overnight. It’s a slow process. Because these scale deposits form slowly they tend to be extremely dense which creates two problems:

1. Scale creates a high level of insulation, which reduces the efficiency of the system. In fact, a 1/8 inch thick layer of scale can cause as much as 25 percent loss in efficiency, and
2. Scale can be so dense that any attempt to remove it is ineffective

Sludge deposits can also be hard, dense, and stubborn to remove. Sludge is a buildup of solids that precipitate in bulk boiler water or which enter the boiler in the form of suspended solids. When exposed to high heat levels, which is the case when the boiler is drained, sludge deposits can become baked on.

In addition to reducing boiler efficiency, scale and other deposits formed in the heat transfer path from the boiler flame to the water restrict boiler water circulation. This happens because the surface of the tube the water flows through becomes coarse which increases drag in the boiler circuit. Reduced circulation creates additional problems such as accelerated deposition of minerals, overheating, and untimely steam-water separation.

Because the same amount of steam is being generated as in a boiler system without scale, the steam-water ratio in the scale covered generating tube is increased. The water in a tube effected by scale increases in mineral concentration which in turn increases the chance of more scale forming from the boiler water salts.

All of this can amount to a total failure of a furnace tube due to overheating.

THE EFFECTS OF HARD WATER ON REVERSE OSMOSIS FILTRATION SYSTEMS

If you recently installed a reverse osmosis (RO) unit you need to be aware of a couple of issues that might take place.
The first is the issue of hard water. Filtering hard water through your reverse osmosis unit can create scale, which will reduce the efficiency of the reverse osmosis membrane to produce high quality water.
The way this happens is, hard water typically occurs when water has a high mineral content, usually calcium and magnesium ions. These dissolved minerals cause scale, which can reduce the performance of your reverse osmosis unit and increase your running costs. The scale sticks to the membrane and other internal parts of the Reverse osmosis unit the same way cholesterol sticks to artery walls and creates clogging. The clogging limits the free flow of water and, when scale forms on the membrane, it blocks its ability to allow water to flow through. This totally disrupts the filtration process.
If scaling forms in the membrane the membrane will no longer be able to filter the water to the level needed to produce a satisfactory level of filtration. Overtime, water hardness will reduce the quality and quantity of water the membrane produces. Essentially, it slowly destroys the membrane.
But replacing the membrane more frequently is not the solution. Replacing membranes too frequently can be expensive. A better, more long-term and cost effective solution is to use a water softening system to soften the water before it reaches the membrane.

The process of Water softening removes the calcium and magnesium ions that cause the water to be hard.

Calcium, Magnesium and Iron Minerals in Ground Water

As groundwater makes its way through the earth’s crust it reacts with various gases and minerals (including Calcium, Magnesium and Iron). The water dissolves these minerals until it reaches a point of balance or equilibrium where no more minerals can be dissolved.

These minerals and gases make up the chemical character of the groundwater. The quality of the groundwater therefore varies greatly from one location to another and is influenced by the available minerals, sediments and gases in the Earth’s crust though which the water flows.

For example, water that flows through pores and fractures in rocks typically has a higher mineral content than water not exposed to the same environment. This explains why water derived from deeper sources is highly mineralized.

Dissolved minerals can be measured in several different units or measures. The most common unit of measure for minerals is in parts per million (ppm) of a given weight. One ppm is equal to the weight of one part of the dissolved mineral contained in one million parts by weight of the solution.

Hardness as magnesium and calcium carbonates

The majority of hardness in most water is due to calcium and magnesium carbonates. These calcium and magnesium carbonates contribute to the formation of scale in boilers, water heaters, and pipes. Hardness that can be eliminated through boiling is called carbonate or “temporary” hardness. Any hardness that cannot be removed by boiling is called noncarbonate or “permanent” hardness.

Hardness is easily identified in water by the larger amount of soap or detergent needed to make a lasting lather. As hardness increases, the need for more soap to rises sharply, and an unpleasant curd is formed. Water hardness is one of the most important factors to be considered when preparing a water supply for use in residential and commercial applications.

Corrosiveness

Corrosive water is any water that attacks metal. Corrosion from water often results in “red water” caused by solution of iron. Corrosion is not the only contributor to red water. If water has enough iron in solution form may give the appearance of being red when exposed to air. Acids and strong bases, together with high pH support the electrochemical process that causes the decay of water pipes, steam boilers, and water-heating equipment.

Manganese

Manganese is dissolved from certain rocks and soils. It’s not as common as iron but has many of the same unpleasant features as iron. In its oxidized form manganese creates dark brown or black stains. Large amounts of manganese are frequently related to high iron content and acidic water.
Calcium and magnesium

Calcium (Ca) and magnesium (Mg) are dissolved from almost all solids and rocks, but particularly from limestone, dolomite, and gypsum. Magnesium is found in large measures in sea water. Calcium and magnesium are the primary cause of the development of scale in boilers, water heaters, and pipes. The presence of calcium and magnesium greatly affect the value of water for public and industrial uses.

Iron

Iron (Fe) is also exceedingly common and dissolved from virtually all rocks and soils. Water with a low pH is usually corrosive and may dissolve iron in undesirable quantities from pipe, pumps, and other equipment. More than 1 ppm to 2 ppm of soluble iron in surface water is a typical sign that acid wastes from mine drainage or other contaminated sources is present. More than 0.3 ppm of iron will stain laundry and utensils with a red-brown colouring. In larger quantities iron causes a nasty taste in food processing or when used in beverages, ice manufacturing, brewing, and other processes and may promote the growth of iron bacteria under slight oxidizing conditions and typical groundwater temperatures.