CONSTRAINT initial
  CONCENTRATIONS
    H+     1.d-8      F
    HCO3-  1.d-3      G  CO2(g)
    Ca++   5.d-4      M  Calcite
  /
  MINERALS
    Calcite 1.d-5 1.d0
  /
END

CONSTRAINT inlet
  CONCENTRATIONS
    H+     5.         P
    HCO3-  1.d-3      T
    Ca++   1.d-6      Z
  /
END
