Hardness of water is contributed by following salts except -
Calcium gluconate
Magnesium chloride
Calcium sulfate
Magnisium bicarbonate
The hardness of water is caused mainly by four dissolved compounds.These are Calcium bicarbonate Magnesium bicarbonate Calcium sulphate Magnesium sulphate Presence of any of these salt produces hardness (refer pgno:727 park 23rd edition)
Environment and health