I/O reef crystals.
LOL My whole chemistry course last semester was based on acid base titrations which are the calcium/ carbonate hardness tests lol..
The first bottles in both those test are just die indicators (phenophalen(turns pink to colourless), and methyl purple(the one that turns blue then to colourless))
Your lucky the test kit gives you that chart, the calculations are a bitch! lol. Even the test kit is inaccurate, because you have to get the temp of the water then look at a chate to see what the density of the water is at that temp. then convert it to ml's rather than the conversion thing they give u in the book. then you have to do 3 trials and then the amount of acid or base dispenced... blah blah blah blah 3 hours later you can quantify how much of acid or base is present in a unknown solution. Which in this case base since calium is a base.
Long story short these test are inaccurate! lol But saves you 3+ hours of work to get results haha