# Define exchanger and solutions...
SOLUTION 1                          # Pore water
 Na 1.1; Mg 0.48; Ca 1.9
EXCHANGE 1                          # 5 g soil with CEC = 10 meq/kg, or 0.05 mmol X-
 -equilibrate  1
 X 0.05e-3                          # moles

SOLUTION 2; Na 1e3; Cl 1e3          # Extractant solution
END

USE exchange 1                      # ...put 5 g soil in centrifuge tube
MIX                                 # ...add 20 g 1M NaCl
 2  20e-3
SAVE exchange 1; SAVE solution 3    # centrifuge and decant
END

USE exchange 1                      # repeat extraction, 2nd time
MIX                                 # 20 g new extractant, 2.5 g of the old extractant
 2 20e-3
 3 0.125                            # 2.5 / 20 part of the old extractant
SAVE solution 4
END

MIX                                 # combine the two centrifuged solutions...
 3 0.875                            # 17.5 / 20 part decanted after centrifuging
 4 0.8888                           # 20 / 22.5 idem
USER_PRINT
 -start
 10 print "CaX2 =", (tot("Ca") * tot("water") * 4e5), "meq/kg"
 20 print "MgX2 =", (tot("Mg") * tot("water") * 4e5), "meq/kg"
 -end
END