I have a twenty nine gallon reef tank and I currently have 186 watts of VHO and PC lighting. I mostly keep softies but am trying an acropora as well. The corals do fine, but they don't grow much. I have heard great things about metal halide lights, but am worried about the heat they produce. I want to get a 175 watt Coralife pendant fixture with a 10000k bulb. Would a powerful fan over my open top tank be enough to keep the water reasonably cool? Is it worth it to even try metal halides on such a small tank, or would I be asking for trouble?
Upgrading to Metal Halides
- Thread starter zog
- Start date
the heat from metal halides is grossly over exaggerated.
I kept a 150w'er suspended over a 29g fresh water planted tank, it was about 18" above the tank and there was no appreciable temp change at all (maybe +1degree if that)...
However, like all other lights, if you were to keep it in some type of closed canopy structure then of course you'd have to deal with heat exchange issues, which can easily be taken care of with a small fan or proper ventilation.
They are totally worth it, I wouldn't hesitate for a second.
The only thing with suspended pendants it the amount of light that spreads throughout the room...that can detract from the tank a little, so try to keep the light as close to the water as your comfortable with...I've seen a bunch of enclosed hoods with mh lights suspended 8" above the surface...if they can do that in an enclosed hood I dont see why you couldn't in a free air setup.
I kept a 150w'er suspended over a 29g fresh water planted tank, it was about 18" above the tank and there was no appreciable temp change at all (maybe +1degree if that)...
However, like all other lights, if you were to keep it in some type of closed canopy structure then of course you'd have to deal with heat exchange issues, which can easily be taken care of with a small fan or proper ventilation.
They are totally worth it, I wouldn't hesitate for a second.
The only thing with suspended pendants it the amount of light that spreads throughout the room...that can detract from the tank a little, so try to keep the light as close to the water as your comfortable with...I've seen a bunch of enclosed hoods with mh lights suspended 8" above the surface...if they can do that in an enclosed hood I dont see why you couldn't in a free air setup.
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The change you describe from 186 total wattage to 175 Metal Halide is not that drastic. I personally would not do anything but introduce the new light.
If you have to put a light 18" from the surface, that's a serious heat issue.
In any case, my halides are in a semi-open canopy about 10" from the surface. I have a couple of 4" fans, and the lights don't change anything by more than a degree.
I agree 18" is quite a distance from the top of the tank no sure you would get the full benefit of the light at this distance.
I have 2X400W 20K Metal Halide and 4X32W actinic Power compact suspended 10" above the tank with an open top I do not see more than a 1-2 degree change with the lights on.
I have 2X400W 20K Metal Halide and 4X32W actinic Power compact suspended 10" above the tank with an open top I do not see more than a 1-2 degree change with the lights on.
I have 1 250w mh 8" above my tank. No heat issue at all. I hopefully will be getting the other 250w mh hung tomorrow or monday. I'm still not to worried about the heat. The electric bill I am scared to death of.
The electricity can get up there. WE calculated with my lighting cycle and all the pumps for the calcium reactor skimmer and closed loop, sump return and the power heads a monthly cost of about $50 on electricity