Which is the coolest Metal Halide?

I'm considering getting some metal halides for my new 210 gal tank and I was wondering about how the wattage and kelvins effect the heat of the bulbs. Anybody know which ones are better than others. I already have 628W of T5 lighting so I know I probably want a high kelvin to dim the brightness somewhat plus I need the depth as the tank is 29" high. I'm not really sure. I have 2 retrofits now. One 48" 8x54W and one 24" 8x24W with mostly ATI and UVL bulbs Blue+'s 6500K, 10K, 12K & 14K. The fixtures are only 12 1/4" wide. I don't want a stark look as my signiture shows my preference for a bluer appeal. I'm just curious as to which bulbs are cooler than others.

 

There is no such thing as a cool Metal Halide, they are all hot as $^!#

 

a quick brush when cleaning a tank will teach you just how hot they are.

they all run the same temperature baring over and under driving. the biggest difference will be from the ballast. a cheap ballast will put out enough heat to make you not want halides ever again

 

As stated, there is no such thing. Metal Halide lamps are among the hottest type of bulb manufactured. While there might be some variance in temperature between a 10K and a 20K bulb, they are both going to be hot enough to operate as designed, and they're designed to ionize gasses within a special glass or quartz capsule. That's HOT.

 

I'm looking to add one metal halide in the back middle of the tank so if a particular coral needs it I'll put it underneath it. Sorry for the reflection on the photo but my current tank is on the opposite wall. The other thing is the overflows are in the way on each end and I don't want to melt anything.

 

you shouldnt worry about melting your overflows. Your mh lighting options are endless.
If im not mistaken your tank is 72inches long. if your gonna go with mh I personally would go with one in the center and one on each side. Unless your gonna go with vho, compacts, or t5s you could just have one metal halide in the center probably at least 250w. That would add a "cool" effect. Like the sun shining into the water.

 

like said earlier, all the lamps are fricken hot. period. the ballast is where the heat matters. basically,magnetic ballasts are hot and e-ballasts are cooler. I have lumatek ballasts that you can touch without any damage to flesh, I cant say that for my hamiltons.
It matters if you keep the ballasts in the stand.

 

OK so maybe I shouldn't worry about melting the overflows but if you have a MH directly over an overflow wouldn't that effect the water temperature even more than if it was just over the display tank? By the way the canopy is 15" high which helps me on the heat issue. I have installed 2 fans pointed lengthwise across the bottom backend of the canopy. Should I add more and where and which way (direct or exhaust)? The eggcrate is there to protect the bottom glass from an avalanche.

 

OK so maybe I shouldn't worry about melting the overflows but if you have a MH directly over an overflow wouldn't that effect the water temperature even more than if it was just over the display tank? i think it would effect the temperature less as the warm water would flow into your overflow and go into you sump. thus making your sump the warmest part of your tank giving the water a chance to cool down by going through your skimmer.


By the way the canopy is 15" high which helps me on the heat issue. I have installed 2 fans pointed lengthwise across the bottom backend of the canopy. Should I add more and where and which way (direct or exhaust)? a 15 inch canopy with fans will take away most of the heat.

i think you getting the wrong idea about halides, they are very efficent lighting. in fact they were the most efficent until t5 came out. keep in mind we are talking about averages now as the most efficent halide is more efficent then the most efficent t5 fixture. for are purpose however with aquarium lighting halide falls second to t5 efficency wise. but the difference isnt that great maybe around 7-15% more lumen output then halide on average. so the heat difference between the two isnt that great.
the difference is t5 bulbs are 10x the halide bulb size to dissipate heat. so ofcourse they will appear to put out less heat. a properly sized quality halide fixture will not cook your tank it but it will raise your tempature 4 or 5 degrees(some fans can offset this). If you need a chiller with halides more then likely you will need one with t5's also, just ask scenario he went t5's so he wouldnt have to use one but it looks like he will need one anyway.

everybody supports there own lighting, with a passion so you need to remember that. i use both them both and both have there own uses advantages and dissavantages, dont be a fanboy just be a fan.

i am including some pages i got my lumen per watt ratios from
Why T5 HO Fluorescent Lighting for my Reef Aquuarium?
Luminous efficacy - Wikipedia, the free encyclopedia (wiki has its own sources at the bottom)

 

Well Sostoudt now we're making sense of all this! Now I understand a lot more about this. Thank you.

It's not that I don't want or can't afford a chiller, to me it's just another big piece of equipment that takes up valuable space and only serves one purpose and eats electricity.

I left an email with my lighting guy and we'll see what he comes up with. I want to keep the blue look so my guess would be 15K or 20K bulbs would work.

Is there any difference between the mogel or HQI style? Is either any better than the other?