How can I input water concentrations given in the literature as meq/L?
(from David Parkhurst) “The program only allows equivalents for the definition of alkalinity, no other element concentrations can be input as equivalents, it defaults back to mmol/L for everything but alkalinity. You’ll have to convert to mmol/L for calcium and other non-monovalent elements. Note calcium molality should be .825 mmol/L to give 1.65 meq/L.” • When I ask pH to stay fixed for a solution in contact with atmosphere or in equilibrium with a mineral, why does the pH not stay fixed? A: As a result of the way web-phreeq constructs the input files for phreeqc, phreeqc first equilibrates the solution at your chosen pH, then it reacts the solution with atmosphere (or a stable mineral). During this reaction phase, pH is changed to maintain charge balance. For pH truly to be fixed, a reaction such as a titration with HCl or NaOH (or with an appropriate mineral) would have to be inserted into the input file. Since web-phreeq is designed as a tool for teaching basic modeling, I suggest
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- How can I input water concentrations given in the literature as meq/L?
