What is Water Hardness?
Water is a good solvent and picks up impurities easily. Pure water is tasteless, colorless, and odorless as often called the universal solvent. As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water “hard”. The degree of hardness becomes greater as the calcium and magnesium content increases and is related to the concentration of multivalent cations dissolved in the water.
Why Water Hardness is important?
Many industrial and domestic water users are concerned about the hardness of their water. You may have felt the effects of hard water, literally, the last time you washed your hands. Depending on the hardness of your water, after using soap to wash you may have felt like there was a film of residue left on your hands. In hard water, soap reacts with the calcium (which is relatively high in hard water) to form “soap scum”. When using hard water, more soap or detergent is needed to get things clean, be it your hands, hair, or your laundry.
You can also notice some spots or film on glass dishes after unload them out of in the dishwasher. This is harder water residue, not dangerous, but unsightly. When hard water is heated, such as in a home water heater, solid deposits of calcium carbonate can form. This scale can reduce the life of equipment, raise the costs of heating the water, lower the efficiency of electric water heaters, and clog pipes. Hard water can even shorten the life of fabrics and clothes.
As this picture of an inside of a water supply pipe shows, long-term movement of hard water through a pipe can result in what is called scale buildup. Just as in the human body where blood vessels can be reduced in inside diameter due to cholesterol buildup, water pipes can gradually close up resulting in less water movement through the pipe and a lowering of water pressure.
That is why, the water quality and water hardness is very important both in the industry and in daily life! It is important parameter and has to be monitored constantly.
Measures of water hardness
General guidelines for classification of waters are:
|German Hardness d ºH||French Hardness f ºH||CaCO3 (mg/L or ppm) Calcium Carbonate||Evaluation|
|0 – 4||0 – 7||0 – 71||Very Soft|
|4 – 12||7 – 21||71 – 160||Medium Hard|
|12 – 17||21 – 30||160 – 213||Hard|
|> 17||more than 30||more than 213||Very Hard|
NOTE: Other organizations may use different classifications.
Measuring the Total Water Hardness with AQUAX® Test Kit
The hardness of water can be approximated with AQUAX® Total Water Hardness Testing Kit.
The AQUAX® has been designed in One-Reagent (Hardness Indicator Buffer Solution) for easy, quick and correct determination of water quality by Titrimetric Method. The easy drop-and-see application provides reliable results within few seconds.
RESULT: The number of drops spent during the experiment is recorded as amount of hardness in German unit (°dH).
1 drop = 1 German Hardness (°dH).
Hardness conversion factors
1 German Hardness (°dH) = 1.78 French Hardness (°fH) = 17.8 mg/L CaCO3
The Features of AQUAX®
Its provided with 50 mL Reagent (Hardness Indicator Buffer Solution) and test container in a box.
Shelf-life and storage