question about metal halide lights

I just put some metal halide lights on my tank and it is making green alage to grow like crazy?   I have been running them on a schedule of 9:15 to 8:15 because I read several things that you want to run them for 10 to 12 hours a day.  Am I running them too much to start with?   Any help will be greatly appreciated.

Tony P.

I had the T5's with the blue and white light.

Tony

are you sure it is algea and not that kind of bacteria, i know the med for it is red slime or something like that.  if it is that stuff it will grow no matter how good your lighting is.  just for thought.

Thats a dramatic increase of light. It can cause a algae bloom but will pass. I would increase skimming for a little while. Did you break in your corals to the new light? That kind of change can shock and even kill some corals. I run my MH for about 7 hours a day. Works great.(Vho's for 12 hours)

I would probably start out at 3-4 hours a day. Maybe increase it every couple of days. You don't want to burn them but you also don't want them to lack the light energy.

i agree, you should always acclimate your corals to your light.  if it doesn't kill them it can bleach them.  and since you went from pc to halide that is a big change in light.  you should also lower the length of light when you change your bulbs.  when i went from pc bulbs to halides i left them on for about 3 hours and worked my self up.  so i agree with mike.