How to use Hardness Test Kit ?
- Ensure the test tube is clean.
- Take a 5 ml sample of water into the test tube.
- Take the KH reagent and add one drop, mix and the water sample should turn pale blue.
- Keep adding drops, one by one (remember to count the drops), mixing between drops, until the blue colour turns to yellow. The number of drops, including the first drop, needed to bring about the colour change is equal to the KH value in dKH. Should the first drop of reagent turn the sample yellow then the KH value is below 1 dKH – this is extremely dangerous for fish.