# Simple predominance diagram
PRINT
   -reset false
PHASES
Fix_H+
   H+ = H+
   log_k 0.0
SELECTED_OUTPUT
   -high_precision true
   -reset false

USER_PUNCH
-headings
-start
50 main$ = "<mainspecies>"
60 IF STEP_NO = 0 THEN 100 ELSE 70
70 totel = SYS(main$, n, n$, t$, c)
80 h2o = TOT("water")
90 PUNCH n$(1), c(1)/h2o
100 END
-end
END

SOLUTION 1
   pH        1.8
   units     mol/kgw
   Fe(3)     1e-1
   Na        1e-1
   Cl        1e-1

EQUILIBRIUM_PHASES 1
   Fix_H+ -<x_axis> NaOH 10
     -force_equality true
   O2(g)  <y_axis>
   Fe(OH)3(a) 0 0
END