PHREEQC Model Configuration

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Latest SysCAD Version: 21 September 2021 - SysCAD 9.3 Build 139.29552

Related Links: PHREEQC SysCAD Project Workflow

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First made available in Build 138 (as BETA version). Formally released as part of Build 139. The PHREEQC SysCAD add-on and models documentation is for the latest version of SysCAD.

General Description

PHREEQC is a computer program that is designed to perform a wide variety of aqueous geochemical calculations. It is developed and maintained by the United States Geological Survey. See wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc for further information.

This model allows the user to define the PHREEQC database file to be used in SysCAD and some configuration of its use. The two main functions are to select a PHREEQC Database File (*.dat) provided as part of PHREEQC installation; and then for the selected Database file 'map' PHREEQC species/ions to SysCAD species/ions used in the project. This allows the other PHREEQC models in SysCAD to convert the SysCAD species flow data to PHREEQC species data (and vice-versa) and use the PHREEQC functionality to calculate aqueous equilibrium data.

The model does not do any calculations and has no process links to any other models in SysCAD flowsheets. Its sole purpose is for management and configuration of a selected PHREEQC Database, other unit models performing PHREEQC calculations will reference this model. Therefore, this model is essential if the user wishes to use the PHREEQC functionality in SysCAD.

The user must have a PHREEQC Database file before initialising the SysCAD PHREEQC Model Configuration. See Referenced File for instructions on where to find this file.

NB The user MUST have installed a version of PHREEQC on their computer. Please see wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc for more information.

Referenced File

The file that will be referenced by the SysCAD PHREEQC Model Configuration is the PHREEQC Database file which is provided as part of the PHREEQC installation, e.g. phreeqc.dat.

Sample database files are stored in the database subfolder of the PHREEQC installation. Typical path is C:\Program Files\USGS\Phreeqc Interactive X.Y.Z-NNNNN\database.

Notes:

1. This file is essential for the PHREEQC functionality to work in SysCAD.
2. The file can be saved at any location - it does not have to be saved in the SysCAD project.

Diagram

The diagram shows the default drawing of a PHREEQC Model Configuration unit model.

Inputs and Outputs

There are no connections to this unit.

Model Theory

PHREEQC requires a defined input stream which defines almost all species in ionic form (no phase). At the given conditions (temperature, pressure), PHREEQC returns an output stream which includes aqueous ions in solution and any precipitates (solids) as species.

The PHREEQC Model Configuration defines the mapping of SysCAD species to PHREEQC ions/species to define the required input stream, and the convert the PHREEQC output stream back to SysCAD species.

The PHREEQC implementation allows for inclusion of adsorption calculations in addition to precipitation. The PHREEQC Model Configuration allows for specification of hydrous ferric oxide precipitates, which are used to calculate the total amount of HFO moles for adsorption calculations.

A diagram is provided below to explain the mapping process. Red lines represent the mapping criteria.

Notes:

• Some automatic mapping functions are available to match species based on molecular weights and elements.

• Users can also manually adjust the mappings by selecting matching ions/species from dropdown lists.

• Where more than one ionic breakdown reactions is available for a SysCAD species (defined in IonList.txt), the user can choose which one or combination to use.

• SysCAD species can be selected to bypass the PHREEQC calculations by excluding them from the defined PHREEQC input stream.

• PHREEQC solid and gaseous species can also be excluded from being formed as part of the PHREEQC output stream.

• Ion definitions are provided in IonList.txt. These are used to calculate SysCAD species breakdowns.

Adsorption

• Adsorption is an advanced topic and requires specialized knowledge to implement correctly. The limitations of the PHREEQC database for adsorption calculations must also be understood by the user.
• The user is advised to review the implementation of adsorption in PHREEQC by referring to the PHREEQC manual, available for download along with the software and databases at: https://www.usgs.gov/software/phreeqc-version-3
• In specification of surface reactions in the PHREEQC database, please ensure that the surface type is specified with an underscore in its name, i.e. HFO_wOH, Alumina_sOH, etc., etc.
• Adsorption species in SysCAD are treated as "fictitious species". They are created based upon the total mass/moles of identified species that generate surface adsorption sites.
• SysCAD supports the implementation of both strong and weak adsorption sites, in line with PHREEQC modelling capabilities
• Adsorption includes multiple surface types. (Note that in Build138 beta, only hydrous ferric oxide adsorption was implemented.)

Workflow

The suggested workflow for configuring the model is:

1. On the PHREEQCModelCfg tab page, browse for required .dat file.
2. On the PHREEQCModelCfg tab page, press the Load button to load the .dat file.
3. Map the PHREEQC ions and species to SysCAD ions and species on the PHREEQCConfig tab page. The simplest way to do this is to press the Try Map Species button next to Map on the PHREEQCConfig tab page.
4. If required, make adjustments to the SatIndex on the PHREEQCConfig tab page.
6. If required, set the species reverse mapping Algorithm on the PHREEQCConfig tab page.
7. If required, make any adjustments to the selection of Ion Breakdown reactions on the IonicBreakdown tab page.
8. Once these steps are performed and the mappings are checked, the project can be run.

NOTES:

1. The PHREEQC Direct Calc Model does not require species mapping between PHREEQC and SysCAD. If the user wants to perform PHREEQC Direct Calculations only, then only Steps 1 and 2 are required from the above workflow.
2. Any other PHREEQC unit models such as the PHREEQC Side Calc Model or PHREEQC Reactor referencing this PHREEQC Model Configuration unit model will use the mappings defined.

Data Sections

The tabs and variable names are described in detail in the following tables.

1. PHREEQCModelCfg tab - This first tab requires the user select the PHREEQC database file and has various related options and parameters.
2. PHREEQCConfig tab - This tab requires the user to map the PHREEQC ions/species to the equivalent species/ions in SysCAD, so that PHREEQC stream compositions can be converted to a SysCAD stream and vice-versa.
3. ScdSpMap tab - This tab reports the SysCAD to PHREEQC species mapping as a result of choices made on the PHREEQCConfig tab page, so the SysCAD stream composition can be converted to a PHREEQC stream.
4. ScdIonMap tab - This tab reports the SysCAD to PHREEQC ion mapping as a result of choices made on the PHREEQCConfig tab page, so the SysCAD stream composition can be converted to a PHREEQC stream.
5. IonicBreakdown tab - This tab lists the Ion Breakdown reactions for SysCAD species and allows the user to select which ones to use.
6. LogKAdjust tab - Optional tab, only visible if the ShowLogKTuning option is enabled on the PHREEQCModelCfg tab. Enables entry of LogK values directly in SysCAD.
7. Engines tab - This tab contains information about the PHREEQC Engines.
8. Info tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.

PHREEQC Model Configuration tab page

Unit Type: PHREEQCModelCfg - The first tab page in the access window will have this name.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Tag	Display	This name tag may be modified with the change tag option.
Condition	Display	OK if no errors/warnings, otherwise lists errors/warnings.
ConditionCount	Display	The current number of errors/warnings. If condition is OK, returns 0.
GeneralDescription / GenDesc	Display	This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here. If this field is blank, then SysCAD will display the unit class ID.
This program contains PHREEQC Copyright U.S. Geological Survey (USGS)
Interface...
Acknowledgement	Display	This program contains PHREEQC Copyright U.S. Geological Survey (USGS)
Website	Web Link	https://www.usgs.gov/software/phreeqc
Version	Display	This displays the version of PHREEQC installed on the user's computer
Model...
Select PHREEQC database file
DatabaseFile/DBFile	Input	This is the name of the database file that was created by PHREEQC, e.g. phreeqc.dat. It is chosen from a dropdown list of available databases, which are defined in the cfg file for the project.
Folder/DatabaseFilePath/DBFilePath	Display	The folder where the database file shown above is saved.
CheckSpListForDuplicates	Tickbox	If enabled this will check the PHREEQC species list for duplicates.
CheckForSteam	Tickbox	If ticked, SysCAD will check if steam (H2O(g)) is included in the list of PHREEQC species.
Load		Click on this button to load the required database file. If the model has not been initialised, then the button will show "Init and Load" and when pressed the model will first be initialised and then the database file will be loaded.
DefnStatus	List	If the PHREEQC database file has been loaded and no errors have been detected then will show OK, otherwise will show error message.
SpDBCount	Display	The number of species loaded from the PHREEQC database file.
Sol.Count	Display	The number of solid species loaded from the PHREEQC database file.
Liq.Count	Display	The number of liquid species loaded from the PHREEQC database file.
Vap.Count	Display	The number of gaseous species loaded from the PHREEQC database file.
ElemCount	Display	The number of elements loaded from the PHREEQC database file.
ElemList	Display	The list of the elements used in the PHREEQC database file.
NumUnitsUsingCfg	Display	The number of units models that are using this Model Configuration.
Mapping Tolerances
Discard.Tol.SigDigits	Input	This provides an easy way to change the Discard.Tol.Rel value. For example, 4 here will set 1.00e-4 to Discard.Tol.Rel. If user changes the Discard.Tol.Rel value, this value will also be updated.
Discard.Tol.Rel	Input	The relative tolerance for ignoring species produced from the PHREEQC calculations. If the mass fraction of a species is > DiscardTol and it is not mapped to a SysCAD species/ion then an error is generated.
Convergence Tolerances
ElemBal.Tol.SigDigits	Input	This provides an easy way to change the ElemBal.Tol.Rel value. For example, 4 here will set 1.00e-4 to ElemBal.Tol.Rel. If user changes the ElemBal.Tol.Rel value, this value will also be updated.
ElemBal.Tol.Rel	Input	The relative tolerance for Element Balance (Input - Output). If the relative error is > ElemBal.Tol.Rel then an error is generated. The ElemBal is used in all PHREEQC unit models.
EnthConv.Tol.SigDigits	Input	This provides an easy way to change the EnthConv.Tol.Rel value. For example, 4 here will set 1.00e-4 to EnthConv.Tol.Rel. If user changes the EnthConv.Tol.Rel value, this value will also be updated.
EnthConv.Tol.Rel	Input	Enthalpy convergence tolerance. This is used for iterative enthalpy convergence calculations in SysCAD.
Water adjustment tolerance
WaterAdjust.Tol.SigDigits	Input	This provides an easy way to change the WaterAdjust.Tol.Rel value. For example, 4 here will set 1.00e-4 to WaterAdjust.Tol.Rel. If user changes the WaterAdjust.Tol.Rel value, this value will also be updated.
WaterAdjust.Tol.Rel	Input	The relative tolerance for water adjustment. If the relative error is > WaterAdjust.Tol.Rel then an error is generated.
Adsorption (see also Model Theory - Adsorption)
Adsorption.IncludeCalcs	Tickbox	If ticked additional fields will be shown on this tab and the PHREEQCConfig tab page. These are parameters for the diffuse layer model of Dzombak and Morel (1990), used for multicomponent adsorption.
Hfo...
Adsorption.MolesStrongPerMoleFe / Hfo_sPerFe	Input	Only visible if Adsorption.IncludeCalcs has been enabled. Default values are from Dzombak and Morel (1990) and should be changed with care.
Adsorption.MolesWeakPerMoleFe / Hfo_wPerFe	Input	Only visible if Adsorption.IncludeCalcs has been enabled. Default values are from Dzombak and Morel (1990) and should be changed with care. PHREEQC databases assume these values in the specification of logK for surface reactions (see PHREEQC manual).
Adsorption.SpecificSurfaceArea / SSA_Sorption	Input	Only visible if Adsorption.IncludeCalcs has been enabled. The specific surface area in metres squared per mole of Fe. Default values are from Dzombak and Morel (1990) and should be changed with care. PHREEQC databases assume these values in the specification of logK for surface reactions (see PHREEQC manual).
Adsorption.KeyElement / Key.Elem	List	Only visible if Adsorption.IncludeCalcs has been enabled. The key element can be selected from a dropdown list.
Select equilibrium model to use / Equilibrium model used was specified in database
(Depending on the PHREEQC database file chosen, the user may or may not have a choice of equilibrium models. eg. if using 'pitzer.dat', 'Pitzer' equilibrium model will be used.)
EquilibriumModel	Davies	Use the Davies equilibrium model to perform equilibrium calculations.
	Pitzer	Use the Pitzer equilibrium model to perform equilibrium calculations.
	SIT	Use the SIT (Specific ion Interaction Theory) equilibrium model to perform equilibrium calculations.
ShowLogKTuning	Tickbox	Enable LogK mode for entering LogK values directly into SysCAD. If ticked, then the LogKAdjust tab page will appear.

PHREEQC Config tab page

This tab is used to map the PHREEQC species/ions to the SysCAD species/ions.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
PHREEQCConfig...
SpeciesName		The Species:Long or Short button is used to change the display of the Species names between the Short form, the Chemical compound, or the longer species names.
Map PHREEQC species/ions to SysCAD species/ions
MapBy	List	This will decide whether the mapping of the PHREEQC species/ions to the SysCAD species/ions is based on their Elemental definition (ElemDefn) or Molecular Weights (MolWt). Mapping by Elemental definition is the recommended option.
Map		This will try to map the PHREEQC species/ions to the SysCAD species/ions, based on the MapBy choice.
CheckMap		This will check the mapping of the PHREEQC species/ions to the SysCAD species/ions based on the MapBy choice. Any unexpected results in the current mappings will be displayed as warnings in the Messages Window.
MaximumMWDiff / MaxMWDiff	Input	This is the maximum allowed difference between molecular weights of mapped species without generating a warning.
MaximumChargeDiff / MaxChargeDiff	Input	This is the maximum allowed charge difference between mapped species without generating a warning.
IonMapPhasesAllowed / IonMapPhases	List	Allows user to choose which type of species can be mapped to ions.
ReverseMappingAlgorithm / MappingAlgorithm	Simple Extent	Species are built in order of reaction extent, with no regard for if they are acids, bases, or salts.
	Salts First	Salts are built preferentially. Remaining form acids and bases. Each group is built in order of reaction extent. Recommended in most cases.
SpDBCount	Display	The number of species/ionss defined in the PHREEQC database.
SpUsedCount	Display	The number of species/ions in the PHREEQC database that are used in the project. These are shown on the PHREEQCConfig tab page.
SpMappedCount	Display	The number of species/ions in the PHREEQC database that have been mapped to equivalent SysCAD species/ions.
SpCFECount	Display	The number of species/ions in the PHREEQC database that can be used with CFE (constrained free energy).
DetailedGridView	Tickbox	Global selection. If enabled, more fields will be shown in grid views (tables) including the tables on this page.
CopyToClipboard		Adds a table of data to the clipboard making it available to be pasted into other applications. Columns include SysCAD species, PHREEQC species, SysCAD molecular weight, PHREEQC molecular weight, mapping type and saturation index.
Filter View
Filter		This button will enable or disable the species filter options.
ShowUnmapped (Only visible if Filter is enabled)	Tickbox	When enabled, all species will be displayed. When disabled, only species that are mapped to a SysCAD species will be shown.
Phases (Only visible if Filter is enabled)	All	No filtering of species based on phase.
	Solids	Only show solid phase species, hide other species.
	Liquids	Only show liquid phase species, hide other species.
	Vapours	Only show vapour (gaseous) phase species, hide other species.
	Solids & Liquids	Only show solid and liquid phase species, hide other species.
	Solids & Vapours	Only show solid and vapour (gaseous) phase species, hide other species.
	Liquids & Vapours	Only show liquid and vapour (gaseous) phase species, hide other species.
	IPhase	Only show "IPhase" individual phase species, hide other species. The individual phases shown will depend on the PHREEQC database chosen.
Filters	Display	Always set to 'Content'.
Content (Only visible if Filter is enabled)	All	No filtering of species based on element or name.
	Contains Any Element	This will display all species that contain any of the elements entered in their elemental definition.
	Contains All Elements	This will display only species that contain ALL of the elements entered in their elemental definition.
	Starts with ...	This will display species that start with the text entered based on the short or long species tag depending on the current SpeciesTag selection.
	Contains any ...	This will display species that contain the text entered in the currently displayed short or long species tag.
	Contains All ...	This will display species that contain ALL the separate text entered in the currently displayed short or long species tag.
Select	Input	Only visible if Filter is enabled and Content is NOT set to All. The user specified Elements or text to filter the species list. Refer to Species Filter for more information and examples.
(The following tables (one per phase) display the PHREEQC species/ions from the selected database and the mapped SysCAD species/ions. The user can choose, or change, the mapped SysCAD species/ions using the dropdown list.) (Each table has the following columns (one row per PHREEQC species/ions):)
log10(SatIdx)	Input	The user specified log10 of Saturation Index of the PHREEQC species. This is only available for solid and gas species.
MoleWt	Display	The Molecular Weight of the PHREEQC species/ions.
Charge	Display	Only shown if DetailedGridView has been enabled. The electrical charge of the PHREEQC species/ions.
IsCFE	Display	Only shown if DetailedGridView has been enabled. 1 or ticked = species can be used for CFE (constrained free energy), thus allows a portion of a species to be locked up and not allowed to react.
Index	Display	Only shown if DetailedGridView has been enabled. The index of the PHREEQC species/ions.
MappedIon	List	The user may select the most appropriate SysCAD ion from a dropdown list to map to the PHREEQC ion. The relationship between ions and species in SysCAD is defined on the IonicBreakdown tab page. It is expected that PHREEQC ions would be mapped to SysCAD ions. This column is not shown for solid and gas species.
MappedSpecies	List	The user may select the most appropriate SysCAD species from a dropdown list to map to the PHREEQC species.
IsAdsorptionSp / IsHFO	List/Tickbox	Only shown if Adsorption.IncludeCalcs has been enabled on the first tab page and only for solid species. Identifies the solid species as being able to form Hydrous Ferric Oxide like precipitates. At least 1 solid must be ticked for Adsorption to be included in the PHREEQC calculations.
MapSpByEl	Button	Only shown if DetailedGridView has been enabled. If pressed, SysCAD will try to find the most appropriate SysCAD species to map to this PHREEQC species by matching elemental compositions.

ScdSpMap tab page

This tab is used to display the mapping of SysCAD species to PHREEQC species. This is often a 1 to 1 mapping.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
SysCAD to PHREEQC mapping
ScdSpMap...
(The following table displays all the SysCAD species in the project with its mapped PHREEQC species (if there is one).) (The table has the following columns (one row per SysCAD species):)
Mapping	Display	The name of the first mapped PHREEQC species (if there is one).
MapType	Direct	There is an exact match of species between "SysCAD species database/cfg file" and the loaded PHREEQC database, and the species is allowed by the license option and mapped directly on the PHREEQCConfig page.
	Ions	The species is not mapped on the PHREEQCConfig page, but can be broken down to valid ions (ionlist.txt).
	Unmapped	Species exist in the loaded PHREEQC database, but not in the "SysCAD species database/cfg file". User may consider adding the species to the SysCAD database if it is required.
	Unlicensed	There is an exact match of species between "SysCAD species database/cfg file" and the loaded PHREEQC database, but the species is not allowed by the license option.
MapCount	Display	The number of PHREEQC species that are mapped to the relevant SysCAD species.
MW_Diff	Display	The difference in Molecular Weights between the SysCAD species and the first mapped PHREEQC species (shown in the name column).

ScdIonMap tab page

This tab is used to display the mapping of SysCAD ions to PHREEQC ions. This is usually a 1 to 1 mapping.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
SysCAD Ions to PHREEQC mapping
ScdIonMap...
(The following table displays all the SysCAD ions in the project with its mapped PHREEQC ion (if there is one).) (The table has the following columns (one row per SysCAD ion):)
Name	Display	The name of the mapped PHREEQC ion (if there is one).
MW_Diff	Display	The difference in Molecular Weights between the SysCAD ion and the the mapped PHREEQC ion (shown in the name column).
CalcFormableSp	Tickbox	If selected, SysCAD will show the SysCAD molecular species that can be formed from the selected ions.
(The following fields are only shown if the CalcFormableSp option has been enabled for at least one ion.
Selected Ions:
x formable species from y selected ions
Formable...
SpX	Display	The name of a SysCAD molecular species that can be formed from one or more of the selected ions.

IonicBreakdown tab page

This tab displays the Ion Breakdown reaction for the SysCAD species. SysCAD Ions are defined in the IonList.txt file, normally located in C:\SysCADXXX\BaseFiles folder. The reactions displayed are calculated by SysCAD and represent the ionic breakdown pathway of the species which produces the largest number of product moles. In other words, species are broken down into the smallest possible ions.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
IBR...
Ion Breakdown Reactions for Species
The following table displays all the SysCAD species in the project with their Ion Breakdown reaction/s. The table has one row per breakdown reaction
CopyToClipboard	Species	Pressing the CopyToClipboard button and select Species will copy the ion breakdown for all species. (top table)
	Species And Ions	Pressing the CopyToClipboard button and select Species and Ions will copy the ion breakdown for species and Ions, including further breakdown of larger Ions.
IonListFile		Pressing this button will open the IonList.txt file being used by the project. Note that any edits of the IonList.txt file will only be reflected after model reload and remapping of the species.
Ion Breakdown reactions	Display	The relevant SysCAD species that is assumed to breakdown as per the specified reaction.
Ion Breakdown Reactions for Larger Ions
(The following table displays all the complex ions in the project (if any) with their Ion Breakdown reaction/s to simpler ions.)
Ion Breakdown reactions	Display	The relevant SysCAD species that is assumed to breakdown as per the specified reaction.

LogKAdjust tab page

Only available in Build 139 or later. Only displayed if the ShowLogKTuning option is enabled on the first tab page. This allows the user to enter estimated LogK values directly into SysCAD. This can be done for a range of temperatures but the user must then develop the LogK(T) correlations for implementation in the PHREEQC database.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
Contains	Input	Filter parameter to narrow down list of reactions shown to a single species/ion.
WriteToDB		This will write the entered LogK values to the database file, making any changes permanent. WARNING: This action can not be undone.
Mod_LogK...
(The table has the following columns (one row per reaction):)
Reaction	Display	Chemical reaction as listed in the PHREEQC database.
LogK	Input	Desired LogK value for given reaction. Values entered here will be used in the project but will not be permanent changes unless the WriteToDB button is pressed.

Engines tab page

The number of engines used can be set in the SysCAD configuration (.cfg) file.

Tag (Long/Short)	Input / Calc	Description/Calculated Variables / Options
This program contains PHREEQC Copyright U.S. Geological Survey (USGS)
Global Engines for PHREEQC Interface
Interface...
Status	OK	The model has been initialised correctly and the database file has been found and loaded correctly.
	Init Required	The model needs to be initialised.
	Init Failed	The model initialisation has been attempted but failed.
	Not installed
	Wrong Version
	DLL not licensed
NumCfgsUsingEngines	Display	Only available in Build 139 or later. The number of PHREEQC Model Configuration models in the project which are using PHREEQC Engines.
Reload		If the user clicks on the 'Reload' button, then it will Reload the PHREEQC engine/s.
InitTime	Display	The time taken to initialise the model on the last attempt.
TotalCalcCount	Display	The number of calculations that have been performed mapping the PHREEQC species data to the SysCAD species data. The mappings are required for other units such as the PHREEQC Side Calc Model or PHREEQC Reactor . This is cumulative and may include multiple iterations. It is reset to zero at the beginning of a run.
TotalCalcTime	Display	The cumulative amount of time that PHREEQC engines have been performing calculations. This is cumulative and may include multiple runs.
AverageCalcTime	Display	The average amount of time required for PHREEQC calculatiions. AverageCalcTime = TotalCalcTime/TotalCalcCount.
TotalReloadCount	Display	The number of model reloads that have been performed by all of the PHREEQC engines combined. The reloads are required when an engine switches between models. It is reset to zero at the beginning of a run.
TotalReloadTime	Display	The cumulative amount of time that PHREEQC engines have been reloading different models.
AverageReloadTime	Display	The average amount of time required for a PHREEQC reload. AverageReloadTime = TotalReloadTime/TotalReloadCount.
TotalWaitTime	Display
(Times that Engine instances are locked. The following parameters are shown for each PHREEQC Engine:)
EngineX	Display	The Engine number (X) of the Engine starting at 1.
TimeLocked	Display	The time that the relevant Engine is locked.
Status	OK	The model has been initialised correctly and the database file has been found and loaded correctly.
	Init Required	The model needs to be initialised.
	Init Failed	The model initialisation has been attempted but failed.
	Not installed
	Wrong Version
	DLL not licensed

Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.

	DLL:	ScdPHREEQC.dll	→	Units/Links	→	PHREEQC: PHREEQC Chem Model Configuration
or	Group:	General	→	Units/Links	→	PHREEQC: PHREEQC Chem Model Configuration

See Model Selection for more information on adding models to the configuration file.

Insert into Project

Insert Unit

→

PHREEQC

→

PHREEQC Chem Model Configuration

See Insert Unit for general information on inserting units.