How to use Tetra Test GH & KH liquid test?

[Barry Tetra]

Hello I just bought new GH and KH test kit from LFS and i have no idea how to use them. What does it mean by ‘change the water from red to green’ and ‘from blue to yellow’? I just wasted 20 drop of test bottle and it turn in to green but not red??? I have no idea

 

[Colin_T]

You add 1 drop of the reagent and swirl the phial of water. Wait a few seconds then add another drop and swirl. Continue doing this until the water in the phial changes colour to whatever it's meant to.

If you have really hard water, you can add more than 20 drops and it won't change until you add enough drops.

 

[Essjay]

For the GH test, add 1 drop, cap the tube and shake it. Do the same with the KH test.
If GH turns green, it means your GH is less than 1 dH; if KH turns yellow, it means your KH is less than 1.
But if GH turns red with the first drop, you add more reagent, one drop at a time and shaking the tube after each drop, until the water turns green.
If KH turns blue with the first drop, add more reagent, one drop at a time and shaking the tube after each drop, until it turns yellow.

Count the drops as you add them. For both testers, the number of drops = the GH or KH in dH.

 

[Barry Tetra]

For the GH test, add 1 drop, cap the tube and shake it. Do the same with the KH test.
If GH turns green, it means your GH is less than 1 dH; if KH turns yellow, it means your KH is less than 1.
But if GH turns red with the first drop, you add more reagent, one drop at a time and shaking the tube after each drop, until the water turns green.
If KH turns blue with the first drop, add more reagent, one drop at a time and shaking the tube after each drop, until it turns yellow.

Count the drops as you add them. For both testers, the number of drops = the GH or KH in dH.

Thank you @Colin_T @essjay, Tetra instruction is really confusing some of them even “google translated” it from german.

 

[Essjay]

Back 50 years ago, our chemistry practical exam had 3 sections, one of which was a titration. We did lots of titrations in class to practice for the exam. The GH and KH testers are titrations, so I know how they work