Optional. A negative (or zero) reporting threshold for clamped concentrations. All negative input concentrations are clamped to zero, because PHREEQC rejects negatives; this parameter only sets the value below which the clamping is reported, it does not gate the clamping itself. Concentrations in \([\text{threshold}, 0)\) are treated as floating-point noise (e.g. from MPI partitioning or non-monotone advection/diffusion schemes) and clamped silently, whereas concentrations \(< \text{threshold}\) are clamped and reported via an aggregated warning per speciation step. Must not be positive. Default: -1e-12 mol/kgw (about 0.002 ppb H2, close to laboratory detection limits).

Additional info

From ChemistryLib/CreateChemicalSolverInterface.cpp line 128

• This is an optional parameter.
• This parameter has a default value of -1e-12.
• Data type: double
• Expanded tag path: chemical_system.concentration_warning_threshold
• Go to source code: → ogs/ogs/6.5.9

Used in the following test data files

Used in no end-to-end test cases.