Lighting Dilemma

I've had this 120 gallon tank up for about 9 months now, and when I moved over to this tank (from a 75 2x175watt MH + 4 VHO T5's) I upgraded to 400 watt metal halides, and the first few months things looked pretty good, my caps and a few other corals went through a little browning and then came back okay, but not their best.
All the corals held on and looked real acceptable for a while, and now yeah, the bulbs are getting to be 9mths old too, but everything just looks horrible. Water parameters look normal and I've long suspected that I have been cooking my corals with too much light? I'm really considering going to 250's, but thought, maybe I could build a new canopy for cheaper and raise the bulbs up from their current 8.5" height above the water to something like 13" from the water? Maybe it's a lack of actinic bulbs that isn't stimulating the best colors to come out?
Obviously going to 250's has some distinct advantages; less heat, less energy usage (by the bulbs and chiller). Keeping the 400's is cheaper though. And building a new canopy is probably cheaper than buying a set of 250 watt metal halides, and a pair of T5 actinics.
Thoughts? Opinions? Tell me GIRS....what should I do? should I go to 250s, and admit that 400's were way over sized for a 120? what should I do? should I build a new canopy and...lol /DesktopModules/ActiveForums/themes/_default/emoticons/wink.gif
Thanks everybody,
Andy

 

Yeah, I'll take that off your hands, even if I don't decide to use it right now. I think I'm going to do a canopy rebuild to start with and see how things go from there.

 

20k's

 

Posted By iaJim on 11/14/2010 09:47 PM
Have you thought of raising those lights higher off the water? That's really close. Someone was talking of a recommendation of 20 to 24 inches above the tank. What's your temp?
Yeah pretty much exactly what I'm thinking. I've read that too, I don't think I will be able to get them that high off, but certainly much closer than current. Temp is controlled by JBJ 1/3hp chiller, usually kicks on after 2 hours, and turns back on every hour or so. I'm having a problem with blowing fuses on that thing though too, the chiller is in the closet and I have an exhaust system set up for it, but it's not enough cfm, the temp in the closet goes up, the resistance of the fuse increases and POP. There they go.

The problem is, the lights are enclosed inside of the canopy and cannot be moved upward easily, pretty much, at all without a canopy rebuild.

 

Not according to this study by avancedaquaristonline:

http://www.advancedaquarist.com/2009/1/review/view?searchterm=LUMENARC