100% RO will suck minerals from your machine and break it down slowly .

Is that a question or a statement? Demineralized water will also give you poor tasting coffee. I make R.O. water at home and add spring water until it reads 60-80 ppm per TDS meter. Pure R.O. or distilled water will cause some leaching on metal contact which increases with temperature and contact time. Tried straight R.O. as an experiment and found the smell and taste of water and coffee off putting.