I just started a new tank about three weeks ago. In the past week, my Cladophora ball (which I mail ordered) has started discoloring and I think it's dying. It is in a 12 gallon Nano Cube (24 watts CF) that I fill with half tap and half distilled water. I dose about half a milliliter of Fluorish and Flourish Excel once or twice a week. Any ideas why my Cladophora might be dying? Or how to rescue it?