Nice read, I've given it a quick once over. I'm not sure where it suggests ammonium and urea are good additions? Just because it will be preferentially up taken by some organisms doesn't make it a good idea to add it to a system. You could make the same argument for adding ammonium to a planted freshwater system as it's also a plant's preferred form of N but the practicalities surrounding it's dosing and safety in a closed system mean that NO3 is a much safer source of N. If you give me the volume of your phyto system and how much miracle grow you add I'll crunch some numbers for you. Like I said previously, it all comes down to the levels involved.
