My foxtail seems to be growing okay and is not dropping its needles but it has lost its wonderful green colour and is now a dull green/brown colour. Is this because I am lacking nutrients or is it generally a sign of too low of light levels. My tank has 2.6 watts per gallon, the foxtail is planted in a claypot with soil covered in gravel. I use an iron rich fert once a week. No CO2 due to small tank size, though I am getting some Flourish Excel soon.