i believe you want to use nuts all the way untill the last 2 weeks of flowering... so as soon as you start growing in vegitative(after seedling/clone) you want to use grow juice, then as soon as you start the 12/12 cycle you use bloom juice (and always micro nutes). only in the last couple weeks of flowering do you use only water, and the only reason that is is to make it ok to smoke (and i believe it also puts a mild amount of stress on them which causes them to produce more resin)
but what do i know...
GL
-Cult