Problems precipitating phases at high ionic strengh using trpitz_v1.21

Hello everybody,

I am working on a geothermal application and I try to model halite precipitation during the cooling of a brine in a borehole. Even when the brine is oversaturated by far with respect to halite (say 8 molar) a positiv SI is calculated but there is no precipitation of solids. I tested it for other phases having a comparatively high solubility like CaCl2 or KCl also getting no precipitation. Whereas for phases with a rather low solubilty (and therefore low ionic strengh at saturation) like SiO2(am) the model give results like I would expect them and continously precipitating solids with progressing cooling. 

Maybe somebody of you can help me with that, I have absolutely no idea what I am doing wrong.

Thank you very much in advance.

Fabian