Aquadur^® test strips

Aquadur water hardness test strips are the ideal choice to quickly, easily and reliably determine water hardness. In many industries water hardness is an important parameter in process control and has to be monitored constantly, for example in the textile industry, water works, fish-farming and aquaculture.

Gradation
<55, >90, >180, >270, >360, >445ppm

The hardness of water is expressed in mmol/l or in the older common unit degrees of hardness, whereby it is important to differentiate between German, English and French interpretation:

in Germany: 1 °d = 10 mg/l CaO = 17.8 mg/l CaCO₃
in Great Britain: 1 °e = 14.3 mg/l CaCO₃
in France 1 °f = 10 mg/l CaCO₃
Conversion factors: 1 °d = 1.25 °e = 1.78 °f = 0.178 mmol/l

In the USA, the water hardness is expressed as ppm (mg/l) CaCO₃. Generally, water is often simply classified as "soft water", or "hard water" , the following values apply to these terms:

below 50 ppm CaCO₃ - very soft water
50 − 120 ppm CaCO₃ - soft water
120 - 240 ppm CaCO₃ - medium hard water
240 - 360 ppm CaCO₃ - hard water
above 360 ppmCaCO_{3 -} very hard water

Aquadur is a registered trademark of Macherey-Nagel GmbH & Co., KG