I always presoak the mini cubes for 24-48 hours in ph'd water but that is the extent of conditioning. Thinking the discoloration may be related it the ph swing?
Week 3 veg
6-1000 watt MH
Rockwool mini cubes in grow flow 2.0- hydro
74f 37% humidity
Elite Gardens nutes with cal mag and hydroguard
Not sure what these leaves are telling me... roots look great. Ph has been on the swing since day 1. Moves from 5.8-7 in a day or two