Two Calculation Pathways
Once the input water is given, there are two principal ways to proceed:
button Start: | interpretation & check of a water sample (CBE, calcite saturation, etc.) |
button Reac: | addition of 1 to 4 chemicals (acids, bases, salts) |
In case of reactions you can also start from pure water (button H2O), which then mimics a pH calculator (cf. online demo).
The two calculation paths starting from the input water to the final solutions (Output 1, Output 2) can be summarized as follows:
One Input water – Two Output Solutions
Independent of the chosen path (button Start or Reac) aqion always provides two aqueous solutions:
- Output 1 – chemical equilibrium without mineral phases
- Output 2 – chemical equilibrium with mineral phases
In contrast, the input water (e.g. water analysis) is neither in a state of equilibrium nor exactly charge-balanced.
According to the above schema, the results of the calculations are presented in tables with three columns: Input, Output 1, and Output 2.
The charge-balanced solution Output 1 (of the left pathway) enters the calculation to examine the carbonate system and the calcium carbonate saturation state.
Two Optional Settings
Two optional settings are available:
pCO2 | to establish equilibrium with atmospheric CO_{2} | |
pe value | to establish a given redox potential (pe value) |
These options simulate a so-called open system where the solution stays in contact with an infinite reservoir of CO_{2} and/or O_{2}. Thus, in the first option, a definite amount of CO_{2} is added or removed from the solution in order to establish the given partial pressure of CO_{2} gas. In the second case, a definite amount of O_{2} is added or removed from the solution in order to establish the given pe value (redox potential).