Merck Residual hardness cell test, photometric, photometric, 0.50 - 5.00 mg/l Ca 0.070 - 0.700 °d 0.087 - 0.874 °e 0.12 - 1.25 °f 0.70 - 7.00 CaO 1.2

Residual Hardness Cell Test Spectroquant®, 0.7-7 CaO , 1.2-12.5 mg/l CaCO₃ You can download the safety data sheet here: Safety data sheet