Proper Light Height above tank

[caillou]

Is there any set standard for the height of power compacts above the top of the tank. I'm in the process of upgrading from a 55 to a 75 RR (thanks ----!) which already had a home made hood but it seems so tall. The lights sit 14" above the top of the tank. Would like to rebuild the hood and keep the lights 6 to 8 inches above the top of the tank.
Any thoughts or suggestions??
Thanks,
Scott
:help:

 

[midwest reefer]

i think personally PC's would be better 6-8 inches. I have heard however that the light spectrum does not decrease as the light cuts through air, only as it cuts through water. If your using metal halides though u might want them higher HTH

 

[enomadra]

I had the same problem with my lights. They sat too high so I built this light cage. As you will see it is for VHO but I am sure you could do the same for PC lights. Here is the link to my post.
My light post link

 

[wester97]

my 3x55 watt pc's are sitting right on top of my tank ... scary!

 

[caillou]

Thanks for all your help! I'm new to PC's and wasn't sure of the degradation issues.
Thanks Again!

 

[jlem]

I would just put the lights as high as the canopy and if your corals look like they can use more light then move them down after a week or so. PC's can put out significant heat so to close and then you can run into the water temp issue.

 

[wester97]

I have a nice internal fan in my lights, there isnt much of a temp increase in the "daytime"