You need the micros but also potassium, get something with both to be easy. Since you have a good fish load you shouldn't need nitrate or phosphate. Dose as directed on the bottles and you should see the plants perk up.
I would use Excel or buy Metricide and dilute it. It is best to use it daily as directed. If you use Metricide off label then hunt around for how tos as it isn't just cheaper it is much stronger stuff.
You may have more light over the tank than you want. There are lower watt compact fluorescents in the more attractive 5000-6500K range out there if you decide that is the case. How good are the reflectors on your fixture?
Apons just grow fast, it might not be the lights at all. It is fine to have its leaves draping along the top of the tank and you can just cut off ones that bother you.