Don't use the high nitrogen fertilizer (Plant Prod) - that can give you vegetative growth instead of flowers. I've never understood, however, that's there a problem with urea nitrogen, though perhaps things are different for hydroponics. I'd go with the Schultz also, but the Dyna-Grow should be okay. I use 15-30-15, a pinch in two gallons of water with every watering except during the winter when I cut back.