Macherey Nagel Aquadur test strips

Macherey Nagel Aquadur test strips. Measure total hardness in the range 0 - 445 ppm as CaCO3. 100 strips. The strips measure from <3, >5, >10, >15, >20, >25 deg dH. This is the same as < 53.4, >89, >178, >267, >356, >445 ppm as CaCO3.