You do a: grep HYDRATED_ION_WATER *.c
in the source code and get the files back where this is used.
In the file 'potentials.c' you can check whether it is read okay, or printed out wrongly, or whether it is something with the mixing rule.
in the source code and get the files back where this is used.
In the file 'potentials.c' you can check whether it is read okay, or printed out wrongly, or whether it is something with the mixing rule.