My Cryptocoryne (I think it's a green wendtii, but I'm not sure) is growing dull-colored, narrow leaves, as you can see in the photograph. When I bought the plant, its leaves were broader, and a very bright yellow-green. I have since trimmed the original leaves as they became overgrown with algae, so you can't see them in the photograph.
Could anyone speculate as to whether the plant is showing a nutrient deficiency?
I dose KNO3, KH2PO4, and Plantex CSM+B; I am using a Fluval CO2 20 in a 10-gallon tank (which, to the best of my calculations, brings the CO2 up to around 15ppm), and T5HO lighting.
Here are some new photographs: http://imgur.com/a/hAVwv#0