You can ditch the Superthrive as well. I think Jack's 321 is specifically for hydro, but maybe someone who knows better can correct me.
I think the Organic forum here on RIU has all of the soil guys. You should ask over there. I'm pretty sure that they make soils that can get a plant through it's entire life cycle with just water, and again, please, somebody correct me if I'm wrong about that. I'm a hydro guy.