...but back on topic, we really need to address this "PAR" issue. I would like to state that par treats all wavelengths of the photosynthetic spectrum the same (400 to 700 nanometers)... this is why it is misleading. Let me illustrate: let’s say you constructed a light source that passed through a monochromator that allowed only 700nm waves to pass through and you achieved a PAR value of 50 (this number is for the sake of argument only). You could build a second light source that passed through a monochromator at a wavelength of 460nm and generated a PAR value of 50. Now, you have 2 completely different light sources achieving the same PAR, yet common pigmentations in the tissue of a lot of corals (perdinin, diatoxanthin, diadinoxanthin) would reflect back nearly 100% of the light from the first light source, while very efficiently passing light from the second source. 8O
Not liking 10,000K MH bulbs
- Thread starter dkedrowitsch
- Start date
im thinking about getting 3x400 watt 20k radium bulbs. ive heard that this brand of bulb gives off a very blue color, could i use a combination of light temps. to make the setup seem a bit brighter? im thinking about using the radiums because i want to keep some sps and a carpet. they both require alot of light but i do want a more crisp bluish white color to the tank, any suggestions? in advance thanks 8)
So how do we explain all of the long-time hobbyists that have tried bluer halide lamps and then switched back because of poor results? How do we explain the better growth rates many (myself included) have gotten from higher PAR lamps (despite lower output in the beloved 450nm range)?
Why does a lighting guru like Sanjay Joshi use 10000K German lamps (and formerly 6500 Iwasaki lamps) over his personal tank and the Penn State reef? No blue supplemental lighting BTW. Both are incredible tanks.
Why does Eric Borneman use 6500K lighting (1000 watt halide - extremely high PAR lamp BTW) over his large home tank with no supplemental blue lighting with such great success?
The photosynthetic corals we are dealing with in this hobby are obviously highly adaptable creatures and don't seem to have much trouble transitioning to a wide variety of lighting conditions. IMO this is clearly evidenced by the success of so many hobbyists using so many different forms and types of lighting with the same species of corals (sometimes frags from the same colonies).
Why does a lighting guru like Sanjay Joshi use 10000K German lamps (and formerly 6500 Iwasaki lamps) over his personal tank and the Penn State reef? No blue supplemental lighting BTW. Both are incredible tanks.
Why does Eric Borneman use 6500K lighting (1000 watt halide - extremely high PAR lamp BTW) over his large home tank with no supplemental blue lighting with such great success?
The photosynthetic corals we are dealing with in this hobby are obviously highly adaptable creatures and don't seem to have much trouble transitioning to a wide variety of lighting conditions. IMO this is clearly evidenced by the success of so many hobbyists using so many different forms and types of lighting with the same species of corals (sometimes frags from the same colonies).
DaisyPolyp":6tbfqtbk said:
I agree that it's probably important to see spectral output of a lamp to see where it's radiating energy, but keep in mind, most of the lamps we're talking about here that are high PAR like 10000K German halides and 6500K Iwasaki halides DO put out a lot of their energy in the blue/violet/green range.
I guess the question becomes, even if a coral is adapted to 450nm to 500nm light in nature, does it really matter if it's under 420nm light in your tank? Apparently they make that adaption fairly well. How, I'm not sure, but the results with so many hobbyists/corals over so many years are undeniable.
there is no doubt that people have experienced better results with the 10K or 65K lamps, but those lamps are traditionaly used in green plant appliccations which makes me think that other factors are influencing the end result... such as phytoplankton reproduction rates. The chart I reference does show that chloraphyll A and C both get more benefit (or at least equal) in the higher wavelengths.
First I'd like to say that my corals are growing great under 55K with NO actinic supplement. However, when I change my bulbs I am going 10K(maybe 65K) with the NO actinics.
Now as corals are concerned I think many of you are missing a small factor. It all depends on where the coral was collected/raised. True, they can adapt, but how much?
A coral that was raised under 65K light will obviously adapt better to 65K MH or even 10K. You toss them under 20K bulbs they may not adapt well or at all. Maybe what we need is to do the opposite, 20K halides with 65K NO/VHO bulbs as the supplement. I wonder if it has been tried or is asthetically pleasing?
Now as corals are concerned I think many of you are missing a small factor. It all depends on where the coral was collected/raised. True, they can adapt, but how much?
A coral that was raised under 65K light will obviously adapt better to 65K MH or even 10K. You toss them under 20K bulbs they may not adapt well or at all. Maybe what we need is to do the opposite, 20K halides with 65K NO/VHO bulbs as the supplement. I wonder if it has been tried or is asthetically pleasing?
ChrisRD":1x3h4fzh said:
I've had success with those bulbs too. These bulbs have been around for some time now. Things are changing. I'm sure there are plenty other than myself that will say their corals are healthier under a much more blue spectrum. I can't report one coral loss since adopting this philosophy. It's allowed me to purchase dying pieces for pennies and nurse them back to health in my reef.
ANEMONEBUFF":1x3h4fzh said:
Corals are rarely collected near the surface. If the Kelvin at the surface of the ocean is 5500K-6500K at noon on a clear day, then anything below a meter of the surface will be more accustomed to 10000K and higher. Raised corals will just depend on the reefkeeper, but the consensus is that wild specimens are best raised under 20K.
ChrisRD":1x3h4fzh said:
We force the coral to make that adaptation when there's a change in lighting. Corals will try to carry multiple strains of zooxanthellae. When conditions change, it will release the strains that are either producing too little or too much photosynthetic energy. This is why I believe it's best to keep them in the more natural blue spectrum.
What DaisyPolylp and myself have provided are scientific facts. It's not enough to just say that thousands of other people can keep coral under 10K or 6500K. Not one person on this forum or others can explain why. There are thousands of people that keep goldfish alive in a bowl, but it doesn't mean it's the best situation for the goldfish.
I could easily just say that there are many successful coral farmers that prefer 20K and leave it at that, but we've at least provided facts as to why.
Many corals are collected at a 20K depth. However many acros come from water as shallow as 2-6 feet. These areas are in a greener 65K area. I cannot post photos so look at the Reef Aquarium Vol 1 by Delbeek and Sprung pages 19-20, 23, and 29.
As for aqua cultured corals, many of them are grown in shallow waters or grow out tanks or under 65K/10K bulbs.
As for aqua cultured corals, many of them are grown in shallow waters or grow out tanks or under 65K/10K bulbs.
ANEMONEBUFF":1nkdd7z5 said:
I don't doubt that, but the most successful and respected facilities use the higher kelvin ratings.
Here are some samples:
http://www.drmaccorals.com/sys-tmpl/oursystems/
http://www.xmlighting.com/images/FAMAad_01.jpg
http://www.reefermadness.us/RM-NewsRoom.htm
http://www.reeffarmers.com/ (just click on some specimens to see what they're kept under)
Its pretty common for growers to use a 6500K bulb to grow thier corals, then give them 2 weeks under a 20000K bulb to color them up. Many more use 30" deep tanks in a greenhouse. Others still use 2-6' of ocean.
I plan to use 2, 5500K or 6500K 175w or 250w MH's with 4, 36" 95watt VHO actinics over my 72" tank.
I think this thread proves that a lot of it is looks and everyone has thier own opinons on the subject. Theres arguments for every aspect if you do enough research, which is why its probably the most widely debated aspects of reef keeping.
I plan to use 2, 5500K or 6500K 175w or 250w MH's with 4, 36" 95watt VHO actinics over my 72" tank.
I think this thread proves that a lot of it is looks and everyone has thier own opinons on the subject. Theres arguments for every aspect if you do enough research, which is why its probably the most widely debated aspects of reef keeping.
What supporters of warmer kelvin bulbs have provided are only opinions and nothing else on this thread. What I have provided are facts and samples. It is widely known by scientific researchers that 14K-20K simulates natural light of coral reefs. There isn't much debate if you can't provide anything to support your claim. I would welcome anything you can legitimately provide. It could do nothing but help.
I would love to see some objective analysis done on this topic to finally kill all the rumor/conjecture/speculation that is rampant.
...one more thing I would like to add: Actinic 420 was originally developed to simulate the ocean's natural light at 8' - 15' depths.
...one more thing I would like to add: Actinic 420 was originally developed to simulate the ocean's natural light at 8' - 15' depths.
reefnutz":3bowpxho said:
How long have you been using metal halide lighting over your reef tank? When did you make the switch to 20K?
reefnutz":3bowpxho said:
What have you provided scientific facts of? That blue/green wavelengths are the last to be attenuated in the ocean as you head deeper into the water column? The absorption curves that were posted? This stuff has been debated online for years - no offense, but this is not exactly ground breaking stuff.
You're not addressing a lot of the issues being raised here - you sorta keep saying the same things over and over now.
What studies have been done to show that 20000K lamps are superior to 6500K/10000K lamps in a reef tank? You keep talking about blue light and monochromatic blue lamps as the holy grail of reef lighting, but keep ignoring the fact that 6500K and 10000K lamps DO put out energy in the violet/blue/green wavelengths that are present at depth in the ocean...
reefnutz":3bowpxho said:
People are not just keeping stuff under them. There are many, many THRIVING reef tanks that use this lighting. Some of these folks have tried 20Ks and switched back.
As to why the 6500K/10000K lamps work, see above...
Besides, even if someone isn't positive why something works, but they know it does, that invalidates the fact that it works? Sorry if that sounds a bit silly to me...
reefnutz":3bowpxho said:
What I see are assumptions you're making based on some scientific studies. IMO that doesn't qualify as scientific proof, it qualifies as theory. These assumptions also ignore a multitude of other factors that come into play when comparing conditions on a natural reef with a reef tank.
Obviously people have been very successful with a wide range of lighting choices. If monochromatic blue lamps are clearly the way to go, how come so many hobbyist choose NOT to use them, even after trying them? 20K lamps are not exactly cutting edge - some models have been available for years.
reefnutz":3bowpxho said:
Again, show me the study where 20K lamps are proven to be superior to other lamps over a reef tank. All I see are assumptions and theories in this thread. I just see one group speaking very authoritatively in regards to a topic that even the experts don't speak authoritatively on...
JMHO of course...
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