Halide Q & A
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LED Lighting vs. MH Lighting
LED Lighting vs. MH Lighting
Dear Forum,
I am new here, and am looking to help design custom LED lighting for reef aquariums. I've been reading through the literature on metal halide lamps and have been a bit confused by some things I was hoping someone might be able to clear up.
One is why people say that 20,000K is the closest to natural sunlight. This seems very strange to me because the sun is actually a blackbody with a temperature of approximately 6500K.
Additionally, from looking at the spectrum for metal halide bulbs, such as this one:
https://secure.wikimedia.org/wikipedia/en/wiki/File:Metal_Halide_Lamp_Spectrum.jpg
it looks as if the output has many sharp peaks from specific atomic transitions which should be pretty annoying, and also that if they are actually peaking in the blue, they will emit a huge amount of UV light that would be extremely dangerous. A blackbody at 20,000K has a peak emission frequency of only 140nm while anything under 400nm is considered to be dangerous UV. 140nm is actually well beyond the range which causes skin cancer readily.
Can someone explain what it is that is actually desired in a spectrum for a reef tank? I can't imagine you actually want much UV because it's too dangerous to have in such high intensities indoors. Besides, a simple purple or blue should be sufficient for most fluorescence in the reef, and you almost want more of a yellow for photosynthetic efficiency in terrestrial plants. Are corals that much different in the color of light that their chlorophyll is looking for?
Anyway, any pointers would be helpful. My goal is to produce cheap LED lighting custom for some friend's fish tanks, and possibly to sell in small quantities to other people if there was interest. I think based on everything that I know about fluorescence and biology that LED lights would be a lot more efficient both photosynthetically and in terms of producing safe fluorescent light, but if I'm wrong I'd rather know sooner than later so I can tell my friends to just use MH bulbs!
Also, are MH bulbs very good when it comes to dimming? My initial plan is to make 10,000 lumen LED lamps in a 5500K white with a sharp peak at 440nm, but they would be dimmable all the way down to 100 lumens.
Best wishes and happy new year!
Brian Neltner
LED Lighting vs. MH Lighting
Dear Forum,
I am new here, and am looking to help design custom LED lighting for reef aquariums. I've been reading through the literature on metal halide lamps and have been a bit confused by some things I was hoping someone might be able to clear up.
One is why people say that 20,000K is the closest to natural sunlight. This seems very strange to me because the sun is actually a blackbody with a temperature of approximately 6500K.
Additionally, from looking at the spectrum for metal halide bulbs, such as this one:
https://secure.wikimedia.org/wikipedia/en/wiki/File:Metal_Halide_Lamp_Spectrum.jpg
it looks as if the output has many sharp peaks from specific atomic transitions which should be pretty annoying, and also that if they are actually peaking in the blue, they will emit a huge amount of UV light that would be extremely dangerous. A blackbody at 20,000K has a peak emission frequency of only 140nm while anything under 400nm is considered to be dangerous UV. 140nm is actually well beyond the range which causes skin cancer readily.
Can someone explain what it is that is actually desired in a spectrum for a reef tank? I can't imagine you actually want much UV because it's too dangerous to have in such high intensities indoors. Besides, a simple purple or blue should be sufficient for most fluorescence in the reef, and you almost want more of a yellow for photosynthetic efficiency in terrestrial plants. Are corals that much different in the color of light that their chlorophyll is looking for?
Anyway, any pointers would be helpful. My goal is to produce cheap LED lighting custom for some friend's fish tanks, and possibly to sell in small quantities to other people if there was interest. I think based on everything that I know about fluorescence and biology that LED lights would be a lot more efficient both photosynthetically and in terms of producing safe fluorescent light, but if I'm wrong I'd rather know sooner than later so I can tell my friends to just use MH bulbs!
Also, are MH bulbs very good when it comes to dimming? My initial plan is to make 10,000 lumen LED lamps in a 5500K white with a sharp peak at 440nm, but they would be dimmable all the way down to 100 lumens.
Best wishes and happy new year!
Brian Neltner
JMaxwell
Most Interesting
Reef tank bulb are generally in the 10K to 20K range. My experience is that most poeple like to look of bulbs closer to the 20K range, but balance that with the higher PAR output typically put out by lower Kelvin bulbs for a given wattage. Supposedly coral grows faster with lower K bulbs, but this may just be due to the higher PAR output at a given wattage. In any case, the corals have poor coloration at 10K lighting and below.
Some reefers like to use 10K-ish main lighting and supplement with blue or actinic supplements, often T5, and vary the light conditions throughout the day to simulate the sunrise, sunset effect. This can also encourage certain fish to spawn.
Claims as to what is "natural" is often spurious, but in any case, the light hitting the reef 10-100 feet under the surface is far more blue than light at the surface. Hence the idea that 14-20K bulbs simulate the light coloration at the depth of the reef. Either way, most people would say the corals look far better under bluer light of sufficient intensity.
You can use the internet to see the spectra typically put out in many manufacturers bulbs. As far as I know, desirable wavelengths are all in the visible spectrum.
Some reefers like to use 10K-ish main lighting and supplement with blue or actinic supplements, often T5, and vary the light conditions throughout the day to simulate the sunrise, sunset effect. This can also encourage certain fish to spawn.
Claims as to what is "natural" is often spurious, but in any case, the light hitting the reef 10-100 feet under the surface is far more blue than light at the surface. Hence the idea that 14-20K bulbs simulate the light coloration at the depth of the reef. Either way, most people would say the corals look far better under bluer light of sufficient intensity.
You can use the internet to see the spectra typically put out in many manufacturers bulbs. As far as I know, desirable wavelengths are all in the visible spectrum.
theyammieguy
Active member
Whats the best bulb for a 70w JBJ viper over a mixed reef? Could you also provide a link for the best price? 10k or 14k?
Last edited:
whitesquall
Member
neltnerb....
you have sparked my interest.... idealy.. I think, a light setup which would have seperate adjustment for the intensity of say the 10K and 20K spectrums would be best this way, the individual could set the color temp to ther own desire.
Also, how many watts would the setup use compaired to MH bulbs... would it be a considerable difference?
How much would this setup cost?
And what would the usefull life expectency be on the setup?
I have a 120-gallon reef 48"x24" surface area, if the price is reasonable I'd like to find out more...
-Alex.
you have sparked my interest.... idealy.. I think, a light setup which would have seperate adjustment for the intensity of say the 10K and 20K spectrums would be best this way, the individual could set the color temp to ther own desire.
Also, how many watts would the setup use compaired to MH bulbs... would it be a considerable difference?
How much would this setup cost?
And what would the usefull life expectency be on the setup?
I have a 120-gallon reef 48"x24" surface area, if the price is reasonable I'd like to find out more...
-Alex.
begginer seeking help!
begginer seeking help!
I am new to this and I am wanting to set up a reef tank, I have a 46 gal bow front, 21 in water depth, first question is could I get away with only using 175w MH? Also the tank is 36 inches long, and I have found some combo lighting (MH, T5's, LED moonlights) that I was looking into, the only thing is there is only one MH mounted in the center. Is this going to be adequate for a 36 in long tank? I am wanting to have a peaceful reef tank, some nice fish, and want to be able to grow a wide spectrum of corals. Any guidance would be appreciated.
begginer seeking help!
I am new to this and I am wanting to set up a reef tank, I have a 46 gal bow front, 21 in water depth, first question is could I get away with only using 175w MH? Also the tank is 36 inches long, and I have found some combo lighting (MH, T5's, LED moonlights) that I was looking into, the only thing is there is only one MH mounted in the center. Is this going to be adequate for a 36 in long tank? I am wanting to have a peaceful reef tank, some nice fish, and want to be able to grow a wide spectrum of corals. Any guidance would be appreciated.
Confused about MH
Confused about MH
I just recently purchased a K2 Viper with a 150w 14,000k bulb. It is my first metal halide but I have to say I was disappointed with the color of my coral. I did not know what to expect.
I have very nice color on 2 other tanks. One uses T5's and the other uses VHO.
My question is are all metal halides in need of supplemental 420/460nm light?
It has been my experience that all blue light washes out certain colors like red, yellow, and orange or that even greens do not come across as vibrant. So the use of 20,000k bulbs seems odd to me.
Can someone point me in the right direction?
Confused about MH
I just recently purchased a K2 Viper with a 150w 14,000k bulb. It is my first metal halide but I have to say I was disappointed with the color of my coral. I did not know what to expect.
I have very nice color on 2 other tanks. One uses T5's and the other uses VHO.
My question is are all metal halides in need of supplemental 420/460nm light?
It has been my experience that all blue light washes out certain colors like red, yellow, and orange or that even greens do not come across as vibrant. So the use of 20,000k bulbs seems odd to me.
Can someone point me in the right direction?
Lumen max elites on 60x18x25 tank?
Lumen max elites on 60x18x25 tank?
Hello all, i had been looking at lumen max elites 250w HQI for my 125g 60x18x25 tank this summer and came across a great deal on 2 for $200 from a local reefer who was changing his lights.
Now that i have them and am planning the light rack which i hope to have LED's set on the aluminum rods. Ive taken more notice that the reflectors take up most of the width of the tank.
I thought i read somewhere that these reflectors cast more downward than having a wide light angle, but im looking to conferm that and get your opinions on if these are a good choice.
Also to get your opinion on how far i should have them raised above tank so i can start to plan how tall to build stand and which type of ceiling i choose for my fish room.
Tank will be heavy SpS.
Any help would be greatly appreciated!!!
Lumen max elites on 60x18x25 tank?
Hello all, i had been looking at lumen max elites 250w HQI for my 125g 60x18x25 tank this summer and came across a great deal on 2 for $200 from a local reefer who was changing his lights.
Now that i have them and am planning the light rack which i hope to have LED's set on the aluminum rods. Ive taken more notice that the reflectors take up most of the width of the tank.
I thought i read somewhere that these reflectors cast more downward than having a wide light angle, but im looking to conferm that and get your opinions on if these are a good choice.
Also to get your opinion on how far i should have them raised above tank so i can start to plan how tall to build stand and which type of ceiling i choose for my fish room.
Tank will be heavy SpS.
Any help would be greatly appreciated!!!
Last edited:
Tony Romano
New member
Go as high as you can to 20" or so. This will allow heat to escape and you to work on tank.
Tony Romano
New member
I am at 14" to reflector lip and have sps in bottom of 29" tank. I don't think much is lost in air. You are correct 18" may require you to be lower to prevent lighting up entire area around tank. Also I have no background on my tank and white walls - bounced light.
joseperezred
New member
36' Coralife AqualightPro
36' Coralife AqualightPro
Hey Walter,
Im not sure if your ? Has been answered but I have the same light fixture as you only I have the 24" for my 60gal cube. I thought about doing the upgrade myself about 2 weeks ago but until I finally called Coralife ( by the way #is 1 (800) 255-4527) and was told that it is possible, but too much work and parts that may even be too difficult to find will be needed in doing this upgrade. I don't remember the exact parts but I do remember been told that obviously the ballast would need to be replaced along with the exit cord comming from the fixture itself due to the 250watt ballast have a much thicker round connection also the housing of the bulbs are different, and ofcourse the bulb itself. Oh and by the way they don't have or should I say make a upgrade kit, you will need to get all this yourself. Well hope I was able to help. Good luck.
36' Coralife AqualightPro
Hey Walter,
Im not sure if your ? Has been answered but I have the same light fixture as you only I have the 24" for my 60gal cube. I thought about doing the upgrade myself about 2 weeks ago but until I finally called Coralife ( by the way #is 1 (800) 255-4527) and was told that it is possible, but too much work and parts that may even be too difficult to find will be needed in doing this upgrade. I don't remember the exact parts but I do remember been told that obviously the ballast would need to be replaced along with the exit cord comming from the fixture itself due to the 250watt ballast have a much thicker round connection also the housing of the bulbs are different, and ofcourse the bulb itself. Oh and by the way they don't have or should I say make a upgrade kit, you will need to get all this yourself. Well hope I was able to help. Good luck.
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