What is Salifert calcium reagent ca-1

[KingNebTheGreat]

I recently purchased a Salifert calcium test kit and while I was looking at everything I noticed ca-2 is sodium hydroxide 2%. I can get a big container of sodium hydroxide from my local hardware store for less than $10 cad. Does anybody know what the ca-1 reagent is and if could in theory get a larger container of it for a cheaper price and use it for testing calcium? I did find a thread on here that mentioned that they were "Lavender Granules" but I couldn't find anything past that. Because for me, the cheapest test for calcium is the Salifert one which is $35 cad for 50 - 100 doses but if I can get even just like a 100ml bottle of the ca-1 I could easily get as many tests as could ever need.
Thank you!

 

[KingNebTheGreat]

Scratch that I found a guide
https://www.reef2reef.com/threads/diy-calcium-test-kit.106147

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I am not in a position to claim those linked details are correct. Concentrations matter in a calcium test. Not enough hydroxide won’t precipitate the magnesium. Too much will precipitate the calcium.