If you have spare Korean tests - check Orange with it too.
Or check Cola with old one, to have same substance tested with different tests. It will be more convincing.
Of course Coca-Cola and Orange have similar acidity, Coca-Cola even more acidic, but try to do that just for the sake of completeness and real science.
May be exchange used negative one to the fresh unpacked one? If they have to show them to employer, does it matter which one they will show? Or that test have some unique numbers/serials/codes and employer check them?
If you have spare Korean tests - check Orange with it too. Or check Cola with old one, to have same substance tested with different tests. It will be more convincing.
Of course Coca-Cola and Orange have similar acidity, Coca-Cola even more acidic, but try to do that just for the sake of completeness and real science.
May be exchange used negative one to the fresh unpacked one? If they have to show them to employer, does it matter which one they will show? Or that test have some unique numbers/serials/codes and employer check them?