Ive recently added some plants into my tank. The plants i have are, java moss, java fern, amazon sword, Vallisneria Spiralis, Sagittaria pusilus. These are all doing fine in my tank so far but my Sagittaria Subulata has turned brown and yellow, does anyone no what this could be? My aquarium is a rio 400 (400 litres) with t5 lighting - two 54 watt bulbs with one reflector, this is on for 10 hours a day. I am dosing daily flora 24 and flourish excel. Thanks