I have 2 x 175 watts metal halides over a 65 gallon aquarium that is 24" deep. The lights are 10" above the waters surface. Do you guys think this is sufficient lighting for sps corals and clams? Are the hung to far from the water surface? :?:
I think it sounds pretty good. It's not too much that's for sure. Your height is about right though you could go a bit lower if your heat doesn't rise too much. I have a single 250 Watt MH 10000K that is 6" above the water surface of my 44 gallon and I am very happy. Since I have an open top all I need is a small cooling fan for evap. No problems keeping it cool. I run at 77 degrees and my heater still cycles occasionally.
My maxima clam is very healthy at the bottom of the tank and mine is also 24" deep.
24" deep is quite deep for 175's. You should be able to get away with SPS high up in the tank but clams might not work on the sand bed. Do you have a sand bed? What are the other dimensions of your tank?
You know, esmthiii pointed out something that I totally over looked! Light intensity. I was thinking 175x2=350 Watts and left it at that. The fact that the 175 watters are coming from two points will bring down your intensity at the bottom of your tank as compared to 350 coming from a single point. The intensity would be high just below the light but would fade as you got further away (of course). Now twin 250's would be a very nice consistant intensity across your substrate, just as recommended.
