10 ppm calcium carbonate (hardness) per drop. Typical accuracey +/- 10 ppm
Red is hard water, blue is soft water.
10 drops is 100 mg/l (ppm) CaCo3.
Fill the test vial to the 20 ml line
Add 5 drops of KW13 adn swirl vial to mix
Add reagent KW14 on edrop at a time*
Count the number of drops required fro teh sample to change colour from red to pure blue
Hardness as ppm CaCO3 = drops KW14 used x 10 (Eg 10 drops = 100 ppm CaCO3)
In very hard water areas: Use 10 ml sample with 3 drops of KW13. Multiply drops of KW14 used x x20 (eg 10 drop = 200 ppm CaCO3)
* When adding KW14, hold the dropper bottle vertical (NOT INCLINED). Allow drops to form slowly and drop off under their own weight. Apply gentle pressure to encourage drop formation.