pink is the color that one usually gets after the yellow color and it is indicative of the particle size and the spectrum of light that size of silver reflects. it may also be a contaminant creating a different molecule, but i am not sure what elemant would combine with silver to create this color. it sounds like you are doing all you can short of r/oing your water before distilling. it is certainly easier on your distiller to filter the water in some fashion, and you may look at cleaning your distiller as it may be dirty enough to contaminate the water youre distilling. that squeezes me for all i am worth.
just thought of this - check out solunar periods in making your CS. i have found that the phase of the moon can have huge effects on particle size and time to get the concentration you want, even flavor. the full moon is best, new moon next, (syzygys) and the worst times are at quarter moons. the waning moon seems to be better than the waxing moon, in my experience.