lighting spectrum in a reef

[davejnz]

The popular choice in bulbs/specrum these days seems to be white/blue(12-14k).Most of these bulbs have spectral peaks high in the purple/blue pectrum(420-460nm).Chlorophyll A present in zooxanthellae has maximum absorption around 440nm and around 640nm(red)Chlorophyll B has absorption peaks that are similiar..It seems alot of the bulbs in the market today dont have much output in the red(650nm) spectrum.Obviously corals will grow with mostly blue light but does anyone feel that this other spectrum should be provided to increase photosynthesis rates?
One of the common arguments,is that the red spectrum is the first to be filtered out as depth increases.This is indeed true,but aren't most of our corals collected in somewhat shallow depths in reefs/lagoons that are near shore where they would be subjected to red light.
What is your view/opinion on this subject?What has your experience been while using different bulbs with different spectral peaks?

[dakar]

Love the more advanced thinking threads.... get to use your brain and fancy words too! (thank god for spell check!)

Did a ton of research last night after reading your post Dave. Found a lot of conflicting information. Wish I had some of the high tech gadgets, time and space to actually set up my own test environment to measure things for myself. But the consensus seems to be that almost all of the longer wavelength reds are filtered out around 3 feet of water (lots of variables influence this like the amount of organics in the water column and such). I'll take that is pretty much the standard. There are also measured claims that light intensity is reduced by as much as 50% at only 19 inches of water, but couldn't find whether it's the entire spectrum or just the longer wavelengths that are reduced.

My thoughts tend to lead to how much adaptability each specimen has to being kept in a captive environment. For each generation of a coral propagated/fragged the rules of adaptation should dictate that each new generation would become more sustainable in the current lighting conditions, be it more wide or limited spectrum of visible light. Now moving them from one lighting condition to another we've seen the end results, either they thrive or they perish, granted a lot of other things come into play here as well.

There has to be more taken into consideration, with all of the different bulb manufacturers, color temps, and types (halides, tubes whatever) they all have a tendency to radiate some UV, both UV-A and UV-B, and unfortunately because they all use mercury some bulbs emit UV-C.

Somewhere around here I have graphs that measured the spectrum output of many bulb types, when I was researching my halides I did a lot of research (I'll see if I can dig them up). But most everyone suggested the need for spikes in the red and blue wavelengths. The middle green wavelengths are more pleasing for 'our' eyes as that's where they see best and were not taken into consideration.

Thoughts on how this plays into the newer trend being experimented with of firing halides to start the photosynthetic process, bring VHO tubes in and drop the halides, and photosynthesis continues? What spectrum are the usual T5's focused at as a norm? Are they enough to keep the process going at the same growth levels? The jury is still out. I've only read of some folks experimenting with this technique, has anyone here actually tried it? Drawn any conclusions?

Finding the best of the best lighting for a wide variety of coral we keep together will always be challenging.... but take into mind who are we setting up the lighting for to please the most, our animals or our eyes?

Hopefully my lack of a lot of SW experience is being compensated by a lot of research/experience of others. Though the higher end 460nm actinics definitely show a lot of promise, many coral appear to remain very active under just these lights, both before and after the halides, suggesting there may be more to the shorter wavelength lighting than I thought. Activity in most of our soft/LPS type begins as soon as they come on, the rest only when the daylights come up. Given my halides spike in both red and blue wavelengths that gives me reason to believe there is some benefit to having both ends or full spectrum lighting.

[davejnz]

Here's a couple graphs you might find interesting.

[davejnz]

Seems the red spectrum penetrates alot further than many of us have thought.Whats even more surprising is the photosunthesis rates between 475 and 525nm.Which many of todays bulbs are lacking in that spectrum as well as the 650-700nm range.
Iwasaki seems to be about the most spectrally balanced halide out there but i have found another one that seems to be promising,as far as its spectral plot shows.Its the EVC 250wDE10k

[dakar]

Here is one of the charts I was looking for referencing some 400w halides. The 250's are quite a bit different, stilll looking for them. they did a lousy job with the printing during conversion but it's readable enough. The big spikes are interesting.

[davejnz]

Seems the color lines on the chart are different than the colors that represent the different bulbs in the box on the right.Here are the spectral plots of Iwasaki and the EVC mogul10k.They both seem to have alot of output throughout the spectrum,especially when compared to most 10-20k bulbs that only have peaks in the 420-450 range and slight peaks in the 600nm range.Look at the spectral plot of the AC14k which is very popular over at RC.

[jerryc]

Will iv been wondering about the deferent combinations of lamps
lately as i just replaced my VHO and had always used 2 Super Act
to supplement my 10K/MH. But this time i ordered one White Act and
one super after just 2 weeks i can see my SPS coloring up
more. maybe something else but don't thank so

[dakar]

What we need is a BIG graph showing all of these bulbs at once... less confusing than switching back and forth to read them. But notice the diffences in the colors peaks and intensities that are produced between the 250w and 400w bulbs of the same brand.

[davejnz]

I also use the actinic white with the super actinic.I like the combination of those 2 bulbs with 1 T5 6.5k and 1 T5blue+(450nm).Together,i feel they provide a balanced spectrum.
Dakar,T5 bulbs have spectral peaks similiar to halides.The .6.5k bulb i use has this spectral plot

[davejnz]

I agree Dakar,it would be nice if someone compiled all of these diiferent sectral plots into a chart.It is weird how the 400's and 250's can have different spectral plots even though they are the same brand.
One of the things that the chlorophyll/photosyntesis chart shows is that from 420 to about 520nm,photosynthesis rates are high and then they peak again at 680nm.
Alot of halides currently avilable aren't really providing light in some of these wavelengths.Especially,around the 500 and the 680 range.If you look at the plot for the Iwasaki,it has some really good output from 420 all the way to about 520.It has decent output in the higher range as well

[dakar]

Angel and I were actually discussing the lights last night, and considering the pros and cons of changing out the 2 250's with 400's when we hit the one year change out time for them in the spring. Gauging strictly off the color plots it could be a good thing to get a little better reach into the whole spectrum across the whole tank. Still undecided as yet, having the diverse lighting intensity areas by having the single 400 in the middle and a 250 on each side is serving us well. The added heat is another concern. We've got time to think about it.

If we keep gathering all of the plots we can find I'll try to find an easy way to compile them into some sort of easier to read graph, I'm sure I've got a program that will draw them up nice.

[davejnz]

I wish i could find some more spectral plots on VHO's,URI is known for there quality VHO bulbs yet i cant find one spectral plot on them or even find there website.T5's charts are pretty easy to find.Advanced Aquarist's online magazine has many of the MH's charts in its archives/back issues.

[davejnz]

I'm not sure how those tests were taken or can i explain why the blue wavelengths aren't penetrating as deeply.Your reasoning makes sense,but who knows.I do know that alot of corals are collected from lagoons that are near shore.
Read this article
http://advancedaquarist.com/issues/mar2002/feature2.htm

[dakar]

Did you find any explanation for the differences of the light penetration in coastal areas vs open water? (image diagram3_520_859 you posted above)

Why would the 550ish nm penetrate so much farther. I'd have to wonder if the measurements are skewed a bit. Coastal waters = high nutrients = higher concentrations of phytoplankton, algaes, etc = maybe they are seeing green/yellows at those depths since everything above would be filtering out the rest of the spectrum ? Or am I not holding my head right to see something different?

[dakar]

DOH! I hosed up the post sequence editing my poor spelling.

[EQCM2B]

In looking up stuff I came across this thread. As anyone who has helped me here in the last three weeks I have had a lot of questions about lighting. I have decided to go the way of a single 250 MH in home made canopy. The LFS was recommending EVC ballast and bulbs 250w @ 10k.I had not heard of the EVC line before andI didn't think the price was to bad so I figured I would look to you guys again for guidence.So again for my 46 gallon corner tank 22x22x13x13x13x25 tall, would this be a good combination to grow anything I wanted? I know there will always be somethings that it will probably be to much or to little still but for overall sps and lps, inverts and fishes. Has anyone heard anything bad about EVC bulbs or ballast?

Thanks for the help.

[davejnz]

I havn't heard much about either there ballasts or bulbs.The $ is usually the deciding factor when buying lights so i would shop around before buying.LFS usually jack up the price quite a bit compared to online retailers.How much are they asking for the whole setup?

[EQCM2B]

EVC 250 watt ballast was 145.00, I think EVC bulb 10k SE was about 65.00
Reflector and socket was about 50.00, I am still waiting for him to call me back because he did not have the price for them.

[davejnz]

Too much $ IMO,I would go with a 250 retro(e-ballast,bulb,socket,reflector) from CoralVue($180) or if your a DIY guy,buy a M58/H37 magnetic ballast off of e-bay(i paid $20 and $25 for both of mine),buy a time-tested/proven bulb($60-$80) like Iwasaki,Ushio,XM to name a few.And lastly get a reflector/socket($35).You will have to wire it up and install the components but its really not that difficult.

BTW,it might be better next time to just start a new thread as this doesn't really pertain to this one.

[EQCM2B]

Maybe I'll try that then. got plenty of time no need to rush.