Inverse Modeling

[rajeshrajenthran]

I am using two groundwater samples along the flow path
Initial solution
pH   Na             Ca             Mg             K      Cl-             SO42-     HCO3                    Si            Al
7.76   58.40   128.79   50.61   8.60   181.82   284.92        434                    9.72   0.07
Final Solution
7.31   9007.27   427.29   1018.68   303.50   17898.17   35.55   1781.20        6.47   0.22
but i am getting this kind of errors
Using Cl1 standard precision optimization routine.
WARNING: Mg is included in solution 1, but is not included as a mass-balance constraint.
WARNING: Mg is included in solution 2, but is not included as a mass-balance constraint.
ERROR: Not possible to balance solution 1 with input uncertainties.
ERROR: Not possible to balance solution 2 with input uncertainties.
ERROR: Calculations terminating.
Stopping.

Please give me solution

[ztwatson]

I am not sure if you have your input set up correctly. You should provide your entire input for verification to see what is wrong. You may need to include minerals for dissolution or precipitation. Also make sure your balances and/or uncertainties are in the input.

[dlparkhurst]

You need to include all major elements of solution as mole-balance equations in the inverse modeling setup. You may use -balance; Mg; to include the equation, or probably better is to provide a mineral/exchange source/sink in -phases.

By not including Mg it is ignored in the solution resulting in a charge imbalance in the inverse calculations.