I planted some dwarf hairgrass in my aquarium, which has good lighting and co2, but it doesn't seem to be growing at all! I thought it was supposed to grow like weeds!I have other plants in there, but the ONLY plant that seems to grow is this one called cambodian something...I don't remember the whole name. Everyday that plant grows almost 1/2 an inch taller. But everything else just...sits there. Why?!