cycle lighting.

I ran mine with. I figure,anything photo-synthetic on the rock needs the light, coraline algae etc. Using a timer 10 to 12 hours on and a night period, worked for me and gave the good algae a boost. If the coraline algae can grow more quickly, keep calcium levels high, it will help to keep the undesirable ones (brown and green) in check as well.

definatley run them! your rock will need it.