I use organic nutes in hydro, Pure Blend Pro. I haven't used Earth Juice, but I've always heard that they are good. The only difference from chemicals is that you must tend to the health of the res, keep it well aerated, and provide a home for the critters to thrive in. Also, a good flush every 2 weeks helps the medium to thrive.
With a 24 sqft canopy, you'll want twice the light. Two 600s will provide 50 w/sqft, which is minimum for fat buds.
HTH
