How often are you changing the solution? Mine doesn't smell fishy or algae like. I use botanicare so mostly organic stuff myself as well.

I'd cut your nutes in half and consider some sort of drip or something that will keep your roots more wet while also giving them more oxygen and areation as well but I'm just guessing there. I notice in my grows that when I stop the drip system and just go with DWC (and my plants are in bloom by that time with a BUNCH MORE ROOTS than those have) I lose some leaves etc. My personal thought is that the roots just dry out and die.....but again......merely PONTIFICATING. (but I'd still suggest you do it.....)