*~*New DOW -- Reef Lighting*~*

[Cougra]

It has to do with the colour of the bulb. It takes more energy to produce the high K light, thus less par is produced.


The easiest way to explain K is to picture a fire. The outermost flames are the coolest and give off the most light, actual physical temperature of these flames are between 1600K to about 4500K.
As you get closer to the coals, the colour changes and the fire gets hoter. By the time you come across the extremely hot blue flames you are in the 10,000K to 20,000K range. Although those blue flames are extremely hot, they don't give off that much light.

[Scooterman]

The standard measure that quantifies the energy available for photosynthesis is "Photosynthetic Active Radiation" (aka "Photosynthetic Available Radiation") or PAR. Contrary to the lumen measure that takes into account the human eye response, PAR is an unweighted measure. It accounts with equal weight for all the output a light source emits in the wavelength range between 400 and 700 nm. PAR also differs from the lumen in the fact that it is not a direct measure of energy. It is expressed in "number of photons per second", whose relationship with "energy per second" (power) is intermediated by the spectral curve of the light source. One cannot be directly converted into the other without the spectral curve.

The most efficient bulbs are the metal halides, the high pressure sodium, and the tri-phosphors ADV850, Dulux, Pentron HO, and Aquarelle, about 20-30% more efficient than the average fluorescent. Of note is the comparison of bulbs with same spectrum but different power. The PC6700 with 55 Watt power is significantly less efficient than the 96 Watt version. This trend should be true for other fluorescent types as well, and also for the MH types. Interesting enough, a generic, traditional metal halide does not perform so well when put side by side with more evolved types such as the dense-line emitter MHs (MHN, Iwasaki65 and Optimarc). The HPS deluxe was included in the sample only for completeness, since it has a too low color temperature (2200 K) to be of use as the main light source in planted aquaria. It might be useful as a replacement for halogen/incandescent bulbs used as accent lights though. Normal HPS bulbs were not analyzed due to their poor CRI (around 20).

Well, reading again more I also read contrasting information as for as efficiency, MH over VHO,PC etc, in some case studies, so I'll have to do some more reading also.

[Woodstock]

Spectral analysis of 250 watt bulbs: (remember PPFD = PAR)

http://www.advancedaquarist.com/issu...4/feature1.htm

[TDEVIL]

i have been tagging along, and have learned quit a bit, thank you

i was wandering what you guys thought about this?

this is a quote: "We started to recently offer a very special, energy saving, self ballasted, cool burning,high-power grow light. Our light has 12,0000 lumen output and offers most par watts. The light flicker free, runs on regular 110v circuit and is UL approved in US and Canada.

I have talked with people in the aquarium industry who state that this would be an excellent light for aquarium use as it comes in different kelvin temperatures to better enhance the Coral growth in an aquarium, while providing more effiicient lumens per watt with such a powerful light output.

Please see our light here: http://www.broad-leaf.com/spec-1250.html"

TD

[strat]

ok, back from work thanks alot for the replies. ill definetiely look into the rubber seals. and ill have to look into the different colors of bulbs too. thanks again

strat

[addict]

Rubber seals on halides? Are you talking just around the wire connections, or the bulbs themselves?
I'd be leery of anything rubber being near the halide bulb... could be a fire hazard.
Neither of my halide bulbs have rubber seals, though I do have rubberized endcaps on my PC bulbs and the wire nuts connecting my mogul halide sockets are siliconed.

Maybe I'm just not understanding correctly... (which wouldn't be the first time)

[Scooterman]

He was talking about the VHO Or PC lights.

[addict]

Cool.

Just wanted to make sure people didn't start adding O-rings to their halides... somehow the smell of burning rubber doesn't lend itself to reef enjoyment.

Thanks for clarifying.

[Craig Manoukian]

Scott A. is correct, sorry for the misunderstanding.

[addict]

It's all good Craig.
Are you still coming into Cali anytime soon?

[Craig Manoukian]

Dave, looks like after the 15th of April, yes that ominous tax day!

[middletonmark]

I'd follow JB NY's statement on reflectors and state that at least in my experience, a good reflector does a LOT. Having pulled off a reflector upgrade from Hamilton flat white metal to PFO parallel a few months ago ... a good reflector will do a lot for you.

I find that there are actually `brighter' areas about 6" in front and 6" in back of my MH bulb now with this new reflector. That the major reflection area is brighter than directly under the bulb ... something new with a good reflector

And if you read the papers by Sanjay Joshi in www.advancedaquarist.com [SE MH reflectors were March 2003, he did DE reflectors too] - but my `bright zone' experience lines up just about perfectly with his charts.

Never mind the light coverage now blows away what it was before. I never really considered how important reflectors are ... but now I can't help but think about how much light I'm getting out of every bulb watt.

[JB NY]

Originally posted by jks1
lets throw a wrench in here, why is a 250W 10K bulb considered "more intense" than a 250W 20K bulb? Is this a PAR difference between the bulb, or just a color thing?

It's not a color thing. The 10K lamps generally put out more PAR than 20K lamps, simple as that. The problem with 20K lamps is that mostly they only put out one large spike in a small wavelength (450nm). and little in the rest of the spectrum.

Theoretically there is no reason a 20K lamp could not put out more PAR than a 10K lamp. I think the manufactures just haven't found the right combinations of halides to make this happen yet.

Originally posted by Cougra
It has to do with the colour of the bulb. It takes more energy to produce the high K light, thus less par is produced.

By the time you come across the extremely hot blue flames you are in the 10,000K to 20,000K range. Although those blue flames are extremely hot, they don't give off that much light.

Not entirely true. It does take more energy to make the blue light, but humans see color and perceive brightness different than it really is. So we tend to see greens and yellow as more bright than reds and blues. Really, someone should be able to make a very blue lamp that has high PAR, they just haven't yet.

Spectral curve for a true 12K


Spectral curve for a true 6K

Originally posted by TDEVIL
i was wandering what you guys thought about this?

Please see our light here: http://www.broad-leaf.com/spec-solux.html"

TD

It's just a PC lamp. Not very bright for our applications.

[Scooterman]

Solux? I see these more and more, I like them but not for the fish tank at this time. lol


Also, blue to ultrvilot light your so high in short wavelength, it will not travel as far as the reds would, thus mo power, plane and simple terms. I think I said that right, I have this information somewhere but I need coffee.

[strat]

thanks reefer addict for clearing that up... that would suck to have orings melting to the bulb ill will shoot my uncle an email and try to get some more info.. maybe it'll be useful to others out there too. question, do xm, coralvue, ushio, etc make their own bulbs or are they made by a big manufacturer and then stamped with their logo/name?? and if so, any ideas what manufacturer makes them?? cuz one of the suppliers to my uncle is GE/Sylvania.... thanks again

cheers