Anybody heard of this?

[hitatree]

I was reading an old copy of Natinoal Geographic where there is a topic of certain Corals having a chemical that under UV light, produces a flourescent color. I'm not talking about normal coloring but BRIGHT colors, and different to what the normal daylight spectrum shows. Pictures of a dull gray coral was producing a neon orange color! In open water, scientists have to use very powerful lights with UV spectrum filters equiped on them, but in aquarium uses lights used to accomodate black light posters can work, if it is the right kind of coral.

Just thought I would open a topic having just read this, because with the use of these coral, beautiful night aquariums can be created. It does have to be during the night time for the flourescence really to be appreciated, but if anybody has heard about this and/or has done it, please respond because i'm very curous on this subject.

 

[BONESTOCK]

Actinic bulbs bring out alot of nice colors in corals and anemones.

 

[TheMadNucleus]

All High Kelvin temp Bulbs typically have Peaks in the UV range. That is one of the reasons that they are so popular for reef systems. The exact reasons that were indicated in the NG mag.

In fact you can convert the temperature of the bulb in kelvins to the peak energy in wavelengths using this simple formula:

Wavelength = 2,900,000 nanometers / T (in Kelvin)

so
for a 10,000K bulb = 2,900,000 / 10,000 = 290 nm
for a 20,000K bulb = 2,900,000 / 20,000 = 145 nm

our visable light ranges from 700nm to 400nm

anything greater than 700nm is infared and anything smaller then 400nm is ultra violet. So clearly 290 and 145 have peak energy in the UV range.

Funny thing about this is that these bulbs are giving not only an owner's fish a nice tan but probably the owner as well

I call a 20000K bulb in an aquarium Fish-fry

IMO As aquarist, I think we have to be careful as there is a fine balance that we must strike, in all fairnesss to the creatures we keep in captivity, between the beauty they provide us with, and the health they more than deserve. I'm not so sure that bathing these reluctant guests with huge amounts of UV to make them glow is particularly fair. It may actually be a little selfish on our part. It seems more our duty to provide them with the exact or closest conditions to their natural habitat that we can. Just an opinion, please don't jump all over this - it is a very individual choice.

HTH

Tom

 

[yaksplat]

Tom- nice calcs....the physics III is rushing back...

 

[Guest]

zooxanthella from what I understand, is the food source and element in corals that cause the flourescents... When zooxanthella is healthy, it stores energy from the light and gives off the beautiful colors.. Correct me if I am wrong but it makes sense to me...

 

[TheMadNucleus]

Hey Jim,

Thx for the thumbs up. Man, I knew you'd pick up on this one. I figured, well, he must've gotten sucked into the physic's vortex somewhere in his educational trials and tribulations.



Lata.

Tom

 

[yaksplat]

yup, my 12 credits of physics makes up 6.5% of my 192 college credits. You'd think i'd get sick of learning after the ME degree, but i got bored so i decided to go get a CS degree. I think from now on when i get bored, i'll just go take my car apart.

Jim

 

[Electrobes]

hahaha awesome. Man I have two 55 watt actinics running on 64 watts with a 250 watt XM 10,000K bulb and my water still looks a bit yellow. Looking at the calculations.. I wonder is XM bulbs have a lower than 10,000K issue

 

[TheMadNucleus]

Hey Electro-tubes

Likely that your issue is due to CRI which is a different parameter of the light then temp. The CRI says how close the bulb is in representing the daylight spectrum. For example a bulb with a CRI of 82 has a spectrum that is closer to daylight than a bulb with a CRI 75. These numbers are on a scale of 0 to 100% though they can not be interpreted to mean that one is 7% better than the other as it is a percentage of all color frequencies and how they match daylight.

I can't recall exactly but I think MH bulbs vary MFG to MFG but most lie in the 80's. So it may be that the CRI of your bulbs is what is causing the slight difference. Not 100% sure on this though - it is more a suggestion for you to follow-up.

That's all we need - another parameter to confuse the lighting issue

BTW - a higher CRI is not necessarily better - depends on what you are looking for. For example, Actinic bulbs have their spectrums mostly in the blue so their CRI is very low (like under 30%) because all blue light is not very close to daylight.

Tom