funny color on the marine floor?

[cmhadden]

I think i have a problem. the floor of my tank is turning this brownish red color. i think its from the food that i am feeding the damsels but can't be certain. anybody got any experience with this and how to fix it?

 

[darb2]

unfortunately it is probably cyano.
How much and how often do you feed?
what is your water flow?
What is your water source?
What are your water parameters?

 

[EELectric]

what do you feed them?