Anyone using VDI 2035 spec for heating water in an ASHP.   Been looking at it seems a smart way to go. No chemicals to turn into a muddy soup, good heat transfer etc. Monitor with a simple conductivity meter and pH meter to control to quality of the water going into and in the heating system    By monitoring  Conductivity (80 to 1550 microsiemens) Ph 8.2 to 10 And Scale products below 300ppm   Any one using are there issues? What if any fitters a