EC is mostly BS when it comes to its listed nutrients; they're about as bioavailable to the plants as they are to you. You'll get some iron, and I believe a tiny bit of magnesium, but that's it. The good news is that EC has some CEC, so it will gain nutrients over time rather than sitting inert so long as you keep your column dosed well.
Dose your macros, see what changes. What ever else is left is usually light and CO2 presuming there's nothing wrong with the tank.
-Philosophos