Below 420nm is it necessary?

[Bpb]

Here's an action spectrum for a Favia coral. Unfortunately, I did not include radiation below 400nm, although chlorophylls a and c2 can absorb radiation down to about 350nm. As a footnote chlorophyll a has a shoulder abosrbance at ~383nm. As for coloration, there are only two or three fluorescent pigments that are maximally excited by UV-A/violet radiation. As for coloration, In some cases, this radiation will be beneficial. In photosynthesis, it will be helpful. Is it necessary - no. We can ignore successful reef tanks that have no (or very little) UV-A/violet light.
There is some concern that violet/blue light is harmful to humans' eyes. I'm not an ophthomologist, but I can say that the dose of UV/violet/blue light at noon on a cloudless day could be more than what we'll be exposed to in most aquarium situations. In all my years of keeping marine tanks, I've only seen one fish go blind. As for protection against UV light, many fishes accumulate sunscreens in their eyes through diet - they cannot make it themselves, the pathway for making UV sunscreens is found only in plants.

Interesting that 675 is used nearly as much as 450 is

 

[oreo54]

Intensity/response curves for the endozoic Siphonales Ostreobium taken from within the massive coral Favia.

. The Biological bulletin. Biology; Zoology; Marine biology. 2 500 1000 1500 2000 erg/cm sec (440 nm) Figure 6. Intensity/response curves for the endozoic Siphonales Ostreobium taken from within the massive coral Favia. For sampling position see Figu

Download this stock image: . The Biological bulletin. Biology; Zoology; Marine biology. 2 500 1000 1500 2000 erg/cm sec (440 nm) Figure 6. Intensity/response curves for the endozoic Siphonales Ostreobium taken from within the massive coral Favia. For sampling position see Figure 5. massive coral...

www.alamy.com

 

[Dana Riddle]

Interesting that 675 is used nearly as much as 450 is

I need to edit my post - We CAN'T ignore successful reef tanks where no (or little) UV/violet is available.

 

[Backreefing]

One thing not stated in this thread is glass . Ordinary glass is almost blocks all light below 400nm maybe 5-10% makes it threw the glass . This is to be considered when adding this low of a no light .

 

[oreo54]

One thing not stated in this thread is glass . Ordinary glass is almost blocks all light below 400nm maybe 5-10% makes it threw the glass . This is to be considered when adding this low of a no light .

350nm-ish

 

[Dana Riddle]

One thing not stated in this thread is glass . Ordinary glass is almost blocks all light below 400nm maybe 5-10% makes it threw the glass . This is to be considered when adding this low of a no light .

I think you're confusing acrylic with glass. Here's the transmission of a 400nm LED through the glass ReeFi uses.

 

[Heabel7]

I think you're confusing acrylic with glass. Here's the transmission of a 400nm LED through the glass ReeFi uses.

Those ReeFi lights look very ...... sexy... hahaha kinda got me on this path as they are a bit out of budget and I was thinking reefBreeders but nothing below 420.

Will I get brought below 420 with just 2 ati blue plus. Or would it be better to use to ati atinic

 

[Biglurr54]

I have been wondering about this too. This is what brought me to the lighting form. I have a 400w radium and royalblue and 420 uv led bars on my tank. My corals all look great but my Walt Disney is green instead of gold. The guy I got the frag from had t5 bulbs and his was gold, I gave a buddy a piece of mine and I did t recognize it after a month under radions. I think I'm missing the very low uv spectrum under 420. I have 4 390 uv LEDs but they are under acrylic which I'm assuming filters out the light? Pics for proof!

Halide

16x Luxeon Royal Blues, 8x 420 uv, and 4x 390 true violet. (All under acrylic splash guards).

 

[robbyg]

I think you're confusing acrylic with glass. Here's the transmission of a 400nm LED through the glass ReeFi uses.

UVB (280-315nm) is almost totally absorbed by glass but UVA (315-400nm) is only about 25% absorbed by glass.

 

[Dana Riddle]

Those ReeFi lights look very ...... sexy... hahaha kinda got me on this path as they are a bit out of budget and I was thinking reefBreeders but nothing below 420.

Will I get brought below 420 with just 2 ati blue plus. Or would it be better to use to ati atinic

Probably doesn't matter that much as to which lamp. Here's spectral data of actinic and actinic-white lamps. If the lamps contain mercury, you'll have a line spectrum at 420nm.

 

[Dana Riddle]

No doubt plenty of photosynthesis occurs below 420.. but it can be considered "optional"..

Dan Kelly made that graph and it is based on a compilation I did years ago. To me, it's confusing. See here for the number of fluorescent pigments excited by longwave radiation .

How to Make Corals Colorful, Part One: New Information, With Particular Attention to Blue-Green Fluorescent Pigments

Light intensity and its spectral characteristics play important parts in promotion of coral coloration.

reefs.com

 

[oreo54]

Dan Kelly made that graph and it is based on a compilation I did years ago. To me, it's confusing. See here for the number of fluorescent pigments excited by longwave radiation .
snip

One question.. are most of these "peak" absorption and how "soft" is it in GENERAL.. i.e say 450 +/- 10nm..
Suppose same goes for emissions...
I assume generally behaves like phosphors..

 

[Dana Riddle]

One question.. are most of these "peak" absorption and how "soft" is it in GENERAL.. i.e say 450 +/- 10nm..
Suppose same goes for emissions...
I assume generally behaves like phosphors..

Biomedical researchers looking at wavelengths best transmitted by human tissues found 470nm to be a 'universal' excitation source (hold a flashlight to the palm of your hand and you'll see red light being best transmitted) - hence this is best applied to orange/red fluorescent proteins. I can't say how 'soft' the excitation numbers are - my article reports the excitation source used by researchers in a hundred or so references.

 

[oreo54]

(PDF) Fluorescent Pigments in Corals are Photoprotective

PDF | All reef-forming corals depend on the photosynthesis performed by their algal symbiont, and such corals are therefore restricted to the photic... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

Figure 1. Appearances (A, D, G, H, I and N), normalized radiances (B,...

Download scientific diagram | Appearances (A, D, G, H, I and N), normalized radiances (B, E, K and O) and normalized fluorescence spectra (C, F, L and P) of the coral subjects. The boxed fluorescence panel (M) shows fluorescence spectra of the three major types of GFP-like proteins found in...

www.researchgate.net

 

[hart24601]

Hey Dana, for a typical 420nm how much variance do you see? I thought you posted before you generally get emission ~15nm either direction of the peak, so a 420nm would still produce *some* 410 and maybe even lower?

 

[chicago]

on a purchase note.. what lights can we buy to get below 420... do t5 true atinics help? Seems like true atinics by ATI are the only choice in that range? I used to run super actinics t12 with metal halid and loved them.. bit of a pain changing out ect and the heat with that set up is a discussion for another time..

 

[hart24601]

on a purchase note.. what lights can we buy to get below 420... do t5 true atinics help? Seems like true atinics by ATI are the only choice in that range? I used to run super actinics t12 with metal halid and loved them.. bit of a pain changing out ect and the heat with that set up is a discussion for another time..

Did you see the new BRS video? They go pretty deep into led vs T5 spectrum and you can see several led fixtures that have that near UV better than t5.

 

[chicago]

yep... i have the t5 led fixtures,,, bought on spur of the moment and regretting.. Was thinking the t5 could fill the space of shadows. nor really... going on the for sale page.. I have plenty of led radions running..

 

[chicago]

so if we had to pick a led fixture for best ability to punch actinic below 420 range would it be kessell or radion or perhaps a bar like unit...

 

[Dana Riddle]

Hey Dana, for a typical 420nm how much variance do you see? I thought you posted before you generally get emission ~15nm either direction of the peak, so a 420nm would still produce *some* 410 and maybe even lower?

Here you go...