my tank is 30" tall and i have some short "kyoto grass" in it. but im not sure if they are getting enough light because they are short. my bulb is a 24" 20W Life-Glo fluorescent bulb. would i have to have taller plants to get proper lighting for them? i have had 3 other plants in the tank, but they withered away. also im not sure if the plants are accustomed to the water conditions. i have a high ph, very alkaline, very hard water, and im not sure that plants that come in a tube from topfin would like the water? comments?