must see if you're going the much more difficult route of running benes in hydro.
completely useless otherwise...
there's a reason practically no big commercial greenhouse running companies try to run organic, it's a huge pain in the dick, and can go wrong in a matter of hours.
i know we're individuals, and not large comapnies running multiple greenhouses with multiple reservoirs, but the pros do what they do for a reason, it's usually a good idea to pay attention to what they do, and why they do it.