How To Make Water Harder - What can I use? I plan on buying a gh/kh test kit on amazon
People generally use crushed coral in a media bag placed in the filtration.. I use Seachem Equilibrium in my RO/DI water. It is more controllable.
You can also use cuttlefish bone (found in the bird section) and either place it in the filter or in the tank itself. Its a good source of calcium for snails.
