Sera KH Test for the exact determination of the carbonate hardness in fresh or marine water. The Test is sufficient for 390 °dKH. In a community aquarium the carbonate hardness should be between 5 and 10 °dkH (saltwater 8 to 12 °dkH) in order to guarantee sufficient pH value stabilization.https://www.aquaristikshop.com/aquaristic/Sera-Test-KH-Karbonathaerte/389014/
- Yiannis T. wrote about Sera Test KH Karbonathärte in 2016:
I'been using this product for many years now. Always accurate readings. Also very distinct colours ( from blue to yellow). It lasts for a long time even after opening the bottle.