follow the initial instructions. the water level should just touch the bottom of the fill line. dont use precision syringes for a true 5ml, use the line. (add 10 drops of solution one, shake 10 seconds, shake solution two bottle for 10 seconds) then:
1. add 15 drops of solution two and shake so it mixes (I use a waiving hand type motion). dont rigorously shake like the initial instructions just make sure it mixes with all the solution not just the top half. 15 drops only equals 300ppm of calcium. thats just where I start (dont know why since my calcium is always above 400ppm. could start at 18 drops or anywhere below where your SURE your calcium will be).
2. from there add one drop, cap, shake like described above and repeat (yes you must shake to completely mix the solution after each drop)
3. once it turns from pink to purple you can stop right there. it will take one more drop to reach the blue end color but why waste a drop when I'm sure after 5yrs of using it, one drop past any initial color change from pink is your result. dont go chasing the perfect end color, once it turns dramatically from pink to purple you could be adding several more needless drops looking to color match the end point blue. you arent painting a car, the dramatic pink to purple switch is the real indicator your looking for (just dont forget to add a drop to your calculations after that).