got new lights now i have hair algae!

[-MillerTime-]

I just upgraded on my 75g from 2x175w halides to a 2x250w w/ 2x110w VHO fixture and now i am starting to notice some hair algae popping up. Currently the halides are only on for about 7 hours. I have alot of algae eaters in my tank so it hasnt gotten too bad but i have noticed some of it starting to grow on some coral on the bottom of my tank. Is this due to the new lights, i am upgrading my protein skimmer too but never had a problem with hair algae in the past. Water tests great, Nitrates are undetectable. Just wondering if anyone has any suggestions.

thanks
-Andrew-

 

[jtesdall]

What about phosphates?

 

[-MillerTime-]

well the hair algae is almost undetectable now, either eaten or disappeared, but i still have some brown algae that is appearing on the sand. Tested nitrates and phosphates and both are undetectable. So im not sure what else could be causing the bloom.

 

[Kevin64]

How close are the lights to the tank water? I maybe wrong, but that sounds like quite a jump in light intensity. Have you seen this thread on 72 hours without light? I doubt that it will cure the problem but it will kill off the cyno problem temporarily. It did for me when I moved from a 29 to a 55.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1078532

 

[-MillerTime-]

i have the lights about 8 inches above the tank, is this too low i was kinda wondering how high to put them. This 72 hour thing looks like it might be a good idea but im afraid of what it might do to the corals, i have alot of SPS frags. Does anyone else think this is a good idea to do?

 

[Kevin64]

From what I've found..with metal halide lighting, generally speaking, 6” above the water is sufficient. Remember that for every foot above the tank, you will lose half the intensity. The closer, the better. HOWEVER...if your tank is not use to the more intense metal halide light (going from VHO to metal halide, for instance) or if you are changing bulbs, going from a lower Kelvin rated bulb to a higher one or just changing the bulb after 2500 hours of burn time, you may want to bring the lights up a bit higher, perhaps 12” to 18” off the tank, to give the organisms time to adjust to the increased UV output. Then over a period of a few weeks (how long will depend on how your corals or tank reacts to the new lighting), lower the lights until they are once again about 6” above the tank.

 

[-MillerTime-]

what about the 72 hour thing, do you think i should give it a try, i was thinking maybe i could just run actinics too?

 

[Kevin64]

You could give it a try with just actinics and see what happens. I would first try to siphon out as much of the cyno out that I could just before the lights go out for the evening and then start the limited light cycle. If it doesn't work, then maybe in a month try it with no lights. In the ocean, there are days with limited light source because of weather. I don't know what type of corals you have but I have only softies and a clam. It didn't bother my clam. My tank gets some ambient from the window and room lighting so it's not totally dark in the tank. My zoos, Kenya tree would all lean towards the window light that came in but that lighting would only last until noon. I would only do it if you are going to be around to monitor water params. Don't do it during a vacation. Maybe someone else can chime in with their thoughts on this. Alot of people have had great luck with it and some have lost a few corals because of it. It did make thread of the month on reefkeeping.com.