actually it wasn't ff soil.. it was plain soil mixed with perlite, bone meal, peat moss. But, I have FF on the way and I believe I will be finding out what happens when you don't add too much to it.
Through the veg stage I used advanced nutrients to help out the nitrogen and magnesium, as soon as it went into the flowering stage I just used ph'd water with molasses and I usually use superthrive through the whole thing!