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Hardness Test Kits

Hardness Test Kit - Ready to go Carrying Kit
Our Price: $59.99
Sale Price: $44.99
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Hardness Test Kits

Hardness Test Kits Directions

1. Fill the mixing bottle with the water sample to be tested to the top of the etched mark (25ml); the bottom of the curved surface or meniscus should be exactly level with the mark.

2. Add 15 drops of Hardness Indicator Buffer Solution.

3. If the water turns Blue, no hardness is present and the answer is 0 ppm. If the water turns red or purple, hardness is present and the test should be continued.

4. Add HT-2 Hardness Titrating Solution, dropwise, while the drops are counted, until the water changes to a blue color. This is the end point.

5. Multiple the number of drops times your calculation ratio.
What is hardness in water?

Hardness in water is defined as the presence of cations. Hardness in water can cause water to form scales and a resistance to soap. It can also be defined as water that does not produce lather with soap solutions, but produces white precipitate. Hardness Test Kits are used to determine the amount of hardness in the water

Hard water minerals primarily consist of magnesium and calcium metal cations, and sometimes other dissolved compounds such as bicarbonates and sulfates. Calcium usually enters the water as either calcium carbonate,, in the form of limestone and chalk, or calcium sulfate, in the form of other mineral deposits. The predominant source of magnesium is dolomite. Hard water is generally not harmful to one's health.

Hardness of water may also be defined as the soap-consuming capacity of water, or the capacity of precipitation of soap as a characteristic property of water that prevents the lathering of soap.  Hardness test kits are used to verify hardness.

Permanent hardness is hardness is considered mineral content.  This cannot be removed by boiling. It is usually caused by the presence in the water of magnesium and calcium and/or chlorides which become more soluble as the temperature rises. Despite the name, permanent hardness can be removed using a water softener or ion exchange column, where the calcium and magnesium ions are exchanged with the sodium ions in the column.

Hard water can cause scaling. The left-over mineral deposits that are formed after the hard water had evaporated. This is also known as limescale. Scale can clog pipes, ruin water heaters, coat the insides of tea and coffee pots, and decrease the life of toilet flushing units.

In industrial settings, water hardness must be constantly monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that comes in contact with water. Hardness is controlled by the addition of chemicals and by large-scale softening with zeolite and ion exchange resins.  Hardness test kits can be used to determine the amount of hardness in the water.

How do you measure hardness?

Because it is the precise mixture of minerals dissolved in the water, together with the water's pH and temperature, that determines the behavior of the hardness, a single-number scale does not adequately describe hardness. Descriptions of hardness correspond roughly with ranges of mineral concentrations:

  • Soft:     0-60 mg/L
  • Moderately hard:     61-120 mg/L
  • Hard:     121-180 mg/L
  • Very hard:     >181 mg/L

It is possible to measure the level of total hardness in water by obtaining a total hardness water testing kit. These kits measure the level of calcium and magnesium in the water. Temporary hardness test kits do not normally measure calcium and magnesium levels but normally use an approximation based on some form of alkalinity test. Measuring temporary hardness accurately would involve a series of tests to work out how much bicarbonates and carbonates are present and how much calcium and magnesium is present and what percentage combination there is. In most cases, the temporary hardness kit is a good approximation, but anions such as hydroxides, borates, phosphates can have quite an effect on temporary hardness test kits.

There are several different scales used to describe the hardness of water in different contexts.

  • Parts per million (ppm)
  • Usually defined as one milligram of calcium carbonate (CaCO3) per litre of water
  • Grains per Gallon (gpg)
  • Defined as 1 grain (64.8 mg) of calcium carbonate per U.S. gallon (3.79 litres), or 17.118 ppm
  • Degrees of General Hardness (dGH)
  • One degree American is defined as one milligram of calcium carbonate per litre of water, equivalent to 1 ppm.

How do you softener water?

The most economical way to soften household water is with an ion exchange water softener. This unit uses sodium chloride (table salt) to recharge beads made of the ion exchange resins that exchange hardness mineral ions for sodium ions. Artificial or natural zeolites can also be used. As the hard water passes through and around the beads, the hardness mineral ions are preferentially absorbed, displacing the sodium ions. This process is called ion exchange. When the bead or sodium zeolite has a low concentration of sodium ions left, it is exhausted, and can no longer soften water. The resin is recharged by flushing (often back-flushing) with saltwater. The high excess concentration of sodium ions alter the equilibrium between the ions in solution and the ions held on the surface of the resin, resulting in replacement of the hardness mineral ions on the resin or zeolite with sodium ions. The resulting saltwater and mineral ion solution is then rinsed away, and the resin is ready to start the process all over again. This cycle can be repeated many times.

A water softener works on the principle of cation or ion exchange in which ions of the hardness minerals (mainly calcium and magnesium ions) are exchanged for sodium or potassium ions, effectively reducing the concentration of hardness minerals to tolerable levels and thus making the water softer and giving it a smoother feeling.
The Langelier Saturation Index, sometimes Langelier Stability Index, is a calculated number used to predict the calcium carbonate stability of water. It indicates whether the water will precipitate, dissolve, or be in equilibrium with calcium carbonate. In 1936, Wilfred Langelier developed a method for predicting the pH at which water is saturated in calcium carbonate, called pHs. The LSI is expressed as the difference between the actual system pH and the saturation pH:

  • For LSI > 0, water is super saturated and tends to precipitate a scale layer of CaCO3.
  • For LSI = 0, water is saturated (in equilibrium) with CaCO3. A scale layer of CaCO3 is neither precipitated nor dissolved.
  • For LSI < 0, water is under saturated and tends to dissolve solid CaCO3.
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