This might be a stupid question, but I can't figure out what has changed. I planted my tank about a year and a half ago. The plants I got were pretty and grew like crazy, to the point that it was aggravating. Then I got stuck with this ugly alage so I took out the worst plants and bought some new ones, but they are not growing and wanting to die. I don't understand why I went from beautiful over grown plants to ugly half dead ones. I'm thinking maybe it's my lighting, I still have the same bulb. Do bulbs dim as they get older and should be changed even though they are not burnt? It seems like it's not as bright as it use to be, but I don't know.