--- a/src/Utils.h	Tue Jul 12 12:10:20 2022 +0200
+++ b/src/Utils.h	Tue Jul 12 15:34:17 2022 +0200
@@ -133,6 +133,13 @@
     double mix(double v1, double v2, double c1, double c2);
 
     /**
+     * @brief Calculate water hardness
+     */
+    double Hardness(double calcium, double magnesium);
+
+    double RA_ppm(double total_alkalinity, double calcium, double magnesium);
+
+    /**
      * @brief Return mg/l as CaCO3
      */
     double ResidualAlkalinity(double total_alkalinity, double calcium, double magnesium);