I'm attempting to calculate speciation in a complex brine system and continually receive the ion strength out of range error. The error seems to be focused around the interactions of EDTA4- with Ca2+ and Mg2+. Oxalate also seems to have this same issue.
If I swap the EDTA concentration for the species we expect to dominate, CaEDTA2-, this just moves the error to another species in the calculation. The model seems to give accurate data when EDTA and Oxalate are removed from the calculations.