I have some water wisteria in my aquarium and the leaves toward the back of the plants are turning brown on the edges so i plucked them off. How do you care for this plant? How much light should it get...i have a plant light in the hood. My ph is about 7. Should i fertilize? I am using Flourish Excel-Organic Carbon but it dosn't seem to be making a difference. I have 3 tiny Tigar Barbs and 1 Blue Dwarf Guarami in my 20 gal tank.