let me elaborate more on the rockwool, if using RW your going to want to run it less for the cubes retain much water, those cubes are small and i dont use large ones myself, so i can only assume you will be moving them into larger blocks or slabs right? i use 1inch cubes in clay pellets, since the clay donest hold water i have the luxury to run often cus the roots are very airy, i believe GH waterfarms say to go 24/7 and many around here do that with no ill effects, i drip using rings on a tray in clay for 15 mins ever hour, if your gonna have them break out of the cube and grow in clay may want to add more pump time, for exclusive cube growing sonomacoma is dead on, couple times a day should do it