My LR is starting to turn a brown color?

[Mylilocean]

It only on some of my rock, and its started to get like a fine hair aglae also(green brown color). Is this normal and OK, or no. How do I fix it, tank is about 4 1/2 months old and it just now started. Run my light 12-9 PC's. LEt me know

 

[tazdevil]

Sounds like bryopsis. Normal for a new tank at this time period. Check this page out:

http://www.reefs.org/hhfaq/pages/main_p ... _algae.htm

Make sure to keep up with water changes, and that your using Ro or Ro/di water from a source that is current on their cartridge changes.