Command line¶

Installing the package provides a ctchem command.

Full report¶

$ ctchem report --ph 8.2 --temp 32 --calcium 450 --alkalinity 250 \
      --conductivity 2400 --chloride 180 --sulfate 120
pH of saturation (pHs): 6.821
LSI: 1.379  [scale_forming]
    LSI +1.38: scale-forming; calcium carbonate will tend to precipitate.
RSI: 5.443  [severely_scale_forming]
    RSI 5.44: heavy scale formation expected.
PSI: 5.59  [scale_forming]
    PSI 5.59: scale-forming tendency.
AGGRESSIVENESS INDEX: 13.251  [balanced]
    AI 13.25: non-aggressive water.
LARSON SKOLD INDEX: 1.516  [severely_corrosive]
    Larson-Skold 1.52: high corrosion rates on mild steel expected.

A single index¶

$ ctchem lsi --ph 7.5 --temp 25 --tds 400 --calcium 240 --alkalinity 180
LSI = +0.190

The psi subcommand takes no --ph (the Puckorius index uses an equilibrium pH):

$ ctchem psi --temp 25 --tds 400 --calcium 240 --alkalinity 180
PSI = +6.776

Precipitation potential (CCPP)¶

The ccpp subcommand reports the mass of CaCO₃ that must precipitate (+) or dissolve (−) to reach calcite saturation, in mg/L as CaCO₃:

$ ctchem ccpp --ph 8.0 --temp 30 --calcium 900 --alkalinity 250 --tds 2000
CCPP = +88.28 mg/L as CaCO3

CCPP is sensitive to the ionic strength, and the TDS estimate is only a rough guide, so pass --ionic-strength (mol/L) to override it with a measured or model-derived value. See CCPP for the method and caveats.

JSON output¶

Add --json to any command for machine-readable output:

$ ctchem lsi --ph 7.5 --temp 25 --tds 400 --calcium 240 --alkalinity 180 --json
{"lsi": 0.19}

Provide either --tds (mg/L) or --conductivity (µS/cm); they are mutually exclusive. Invalid inputs exit non-zero with a clear error message.