Hardness: Water hardness is also very important in the planted aquarium.
Hardness: Water hardness is also very important in the planted aquarium. It is vital to the health of both fish and plants, though this parameter is often ignored by most new fishkeepers. Water hardness comes in two forms, general hardness (GH) and carbonate hardness (KH), which are measured in parts per million (ppm) or degrees (dGH or dKH).