new lighting/algae problem

[scottyc]

need some advice, i recently upgraged my lighting from 260w pc to 500mh + 192w pc. i am running the new lights(actinics) from 3-11 pm & the halides from 4-10pm. i started getting what looked like popcorn butter,yellow color on the rocks. now most of my live rock is getting a green tint to it. i obviously now need to cut my lighting back,but how much? i have some lps in the tank. also should or can i scrub the rocks some to get the green off?

 

[scottyc]

ok thanks everyone!

 

[reefraff]

What are your water parameters? You just made a gigantic increase in light which will allow the algae to take advantage of any excess neutrients in the water.
Did you acclimate the tank to the increase in lighting? I would have started with a couple hours of halides a day and leave the actinics where they are. That would be more to not shock your poor corals than to prevent algae.
Good luck

 

[scottyc]

thanks reef,ive cut my lighting back to actinics on for 6 hours and the halides to 4 hrs a day,im noticing the rocks clearing already. my parameters have been excellent, temp is 80.6, sg 1.025, calcium 465, alk 9, only a trace of nitrates but my kit(fastest-junk) always reads a trace.