I have several Echinodorous cordifolious (Spade leaf Radican Swords) that are in the 18 to 24 inch range. Suddenly the newer growth on these plants is turning reddish brown. Anyone have an idea what they could be lacking? dKh = 5.5, pH = 7.4, Lighting 130 Watts on 70 gallon tank. (Croma 50's, Daylight, and Actonic bulbs. Dennis