http://forum.aqua-fish.net/ A forum devoted to aquarium fish, plants, techniques and fish keeping as a whole. en http://forum.aqua-fish.net/?topic=what-is-dh-#1 What dH stands for in the following quote: Water: pH: 7.0-7.7, 6-12 dH, 21-24 °C (70-75 °F) original post: May 24, 2007, 9:57 am anonymous 2008-05-03 http://forum.aqua-fish.net/?topic=what-is-dh-#2 dH: 6-12 means your water should not be hard (starting at 6, limiting to 12). For instance, such water is suitable for Discus species. Test kits will tell you water hardness values in your tank. -Michael- anonymous 2008-05-03 http://forum.aqua-fish.net/?topic=what-is-dh-#3 Michael is right. Topic moved, it doesn’t belong to coldwater and koi. jan 2008-05-03