To a chemist, water hardness is a measure of divalent cations (Ca+2, Mg+2, Fe+2, etc). That's what a GH test kit measures. Apparently you have water with a high total mineral content, but low amounts of the +2 ions that contribute to hardness. People with less understanding of chemistry might refer to any water with high mineral content as "hard". You can add heaps of sodium, potassium, chloride, sulfate, bicarbonate, etc into water and it won't change the GH hardness.
Originally Posted by Dart27
Thank you. Other people have told me I have soft water so I was very confused what fish I should be looking for. So I should stay away from the tetras that don't do well in hard water, correct? Livebearers would do well, etc.