Duncan tips brown, base white??

[bucfan]

Noticed my duncan tips are getting brown and the base is getting white. I have it high in the back of my tank under the return so it's somewhat shaded. What is this a sign of?

 

[Connie]

IME they like medium light, medium flow and lots of food. The more you feed them, the more they will grow. I feed mine chopped table shrimp, squid or LPS Ultra Pellets.