Is this good or bad?

[cnoffs]

Bak from 3 week vacation only I find my tank rocks, plants, top third of nemo, covered in this chocolate looking stuff. This is a fairly new tank. All numbers are good. What is this? And what about nemo? He's actually changed color !!!

 

[mainereefer]

sounds like diatoms. the tank is cycling, how long are lights running?

 

[cnoffs]

Lights r on 12. Off 12. This is not a reef tank. Just fish and rock.

 

[mainereefer]

cut light back to 6 hrs a day. everything will be much happier

 

[cnoffs]

Thank you. I will definitely do that.