non-carbonate hardness nch - water softening1

Question

Non-carbonate hardness (NCH) - Water Softening

1. Permanent Hardness, not removed by heating water

2. Ca⁺², Mg⁺² combining with ions outside of alkalinity such as Cl^-1, NO₃^-1, SO₄^2-

3. NCH = TH-CH   (if alkalinity is equal to or greater than TH, then NCH is zero)