Taylor Test Kit Question

[saint_malachy]

When testing for FC, you use 5 drops of the 1st solution, and then 5 drops of the second. I don't see where you would ever use these independently. How come a single solution can't be produced?

 

[JasonLion]

It sounds like you are using the DPD chlorine test. The first 5 drops adjust and buffer the PH of the sample. The second five drops are a dye that reacts with chlorine. For the dye to react in a predictable way, the PH must already have been adjusted. If you mixed them in advance, the PH would be wrong in some places during the initial mixing and the dye would not react in a uniform and predictable way.