LSI & Dosages with Orenda – Calcium Hardness

Calcium Hardness

Calcium Hardness is the concentration of dissolved calcium ions (Ca2 +) in the water, including dissolved calcium compounds such as:

  • Calcium Carbonate (CaCO 3)
  • Calcium Bicarbonate (CaHCO 3+)
  • Calcium Sulfate (CaSO 4)

Calcium hardness is most often expressed as ppm CaCO 3, because it is a convenient weight measurement converted from a molar measurement. Some water tests show ppm (or mg/L) of Ca2 +. But for the Orenda Calculator™, we use ppm CaCO 3 like most standard swimming pool test kits.

Learn more about calcium hardness here.