purple bulbs - effects on corals, algae?

@Reeferbatman - first of all, thank you for your responses. But to clarify, the data and graph you posted - is that specifically for corals, or for any photosynthetic organism? In other words, is this for land plants? Algae? Because if so, having lots of red in the spectrum would also grow lots of algae. And would also theoretically grow zoo-x in corals, potentially causing them to brown out.

Based on your graph, I might suppose that it would be better to have more blue/actinic and less red, to reduce algae and zoo-x growth and allow coral colors to come through. And to provide just enough red spectrum to allow some growth, and also to feed the coral to provide energy as well.

In other words (and sorry to be so long-winded) - might your graph actually show the opposite of what you are saying, that too much 10K or red light may actually cause browning and algae growth?
 
@Reeferbatman - first of all, thank you for your responses. But to clarify, the data and graph you posted - is that specifically for corals, or for any photosynthetic organism? In other words, is this for land plants? Algae? Because if so, having lots of red in the spectrum would also grow lots of algae. And would also theoretically grow zoo-x in corals, potentially causing them to brown out.

In other words (and sorry to be so long-winded) - might your graph actually show the opposite of what you are saying, that too much 10K or red light may actually cause browning and algae growth?

Good question...

Yes, that graph is a summary of all light needed in both plants and corals (and also algae's).

In addition too much 10,000k can bleach out your corals you are right.

If you experience bleaching, certainly cut down on your 'white light' either in time period or intensity.

As to more light causing excess algae, this is relative to each tank but can be a problem. If you have excess nutrients (in a new tank for example) that extra photosynthetic food (light) can lead to a possible surge in nuisance algae.

But if your nutrients and such are in check and 'good stuff' like coralline are in your tank, the bad algae shouldn't have much to work with or grow on. Personally I wouldn't want to starve my whole tank of light in hopes of keeping some nuisance algae at bay.

But then again I have critters to take care of it too - foxface rabbitfish, emerald crab, etc.


As to the browning of zoo-x I wouldn't worry. all the needed lower spectrums will be there in addition so all the colors of the zoo-x will be represented.

In addition I read a lot on biology and evolution, and tend to follow through with the thought that if you support the coral via good light the coral will then grow to rely more and more upon photosynthetic gains as opposed to 'filtering' food from the water... This only means the photosynthetic cells will be favored and multiply that much faster...

Theoretically leading to a more colorful 2nd generation of coral once it splits, then a 3rd, etc.
 
And to those interested, it does get even more complicated with different spectrums needed for both types of chlorophyll in the corals/plants...

chlorophyllab.jpg


Chlorophyll B is where the coral gets more of its energy (more from the blue/green spectrum too) but Chlorophyll A is the 'good stuff' that the coral really wants... in addition B will increase the capacity to intake/utilize A.

Think of it like I said before, the lower spectrum 'preps' the coral to take more advantage of the higher spectrum offered.

If you were only offering 600-700nm light, the coral could not fully photosynthesize even though that's the most needed part of the spectrum.

Note that even though it really really needs that upper spectrum to fully produce food, the majority of light absorbed is still in that blue/green spectrum - leading to those colors we love in our corals.



So no - offering the full spectrum to the coral will not promote red zoo-x over blue/green coloring in the corals. It may bring out some more colors in the coral, but it will not replace the blue/green coloration.
 
No, you actually need all 3 'bursts' of nm to feed the coral, not just the red...

But that is the most important part. Without it the coral cannot actually "feed".

That is not true at all. Look up light spectrums at 100 feet, corals still grow that deep yet there is pretty much 0 red left in the light spectrum at that point. Blue is the most important photosynthetic part for growth of corals symbiotic algae, not red. Red helps but is used more in growing corals/algae at shallow ocean depths which is why it can fuel algae growth (shallow growing ocean life). Corals can survive with little to no red light without much of a problem.
 
That is not true at all. Look up light spectrums at 100 feet, corals still grow that deep yet there is pretty much 0 red left in the light spectrum at that point. Blue is the most important photosynthetic part for growth of corals symbiotic algae, not red. Red helps but is used more in growing corals/algae at shallow ocean depths which is why it can fuel algae growth (shallow growing ocean life). Corals can survive with little to no red light without much of a problem.

This is sort of what I was getting at with my question of whether the above graphs were for coral or plants/algae. In deep water there is little red/orange/yellow light, and yet corals have evolved to use blue-er light. That's why I question whether the graphs above apply to corals...
 
Corals that grow below 100 feet rely very little on photosynthesis, mostly on filter feeding instead from the nutrients and detritus of the sea currents.

@ roughly 100 feet, photosynthetic corals start to take over, but they are mostly plate like species that expand horizontally to acquire as much light as possible. These are the corals I assume your talking about. They will rely more upon Chlorophyll B instead of A, and hence not have the same growth rate potential as a more fortunate corals that evolved higher and had the advantage of more light and easier Chlorophyll A production.

Even these deep corals that use light are cousins to non-photosynthetic forms of the same species genera. AKA you have both light needing and non-light needing forms of gorgonian fans, etc.

Using these "deep corals" as your "base photosynthetic" needs is not wise, as the majority of species in our hobby come from a higher reef 'biotope' where more light is abundant.

And as you said, those depths are the boundry of [photosynthetic] corals. After that, there is actually no red left at all... that is why [photosynthetic] corals can't grow below even though there is still blue light down another 200 feet or so...



But your main point remains valid, it is in fact difficult to speak in generalities as every species of coral utilizes a slighty different spectrum than the next. Here's an example...

Nice High up Favia on the reef

faviazoo.png


Note how it can fully use the spectrum needed.

And a lower down Acro

acro.gif


Note that the lower Acro has evolved to take in a lower spectrum of light, but it still gets most of it's energy from that 560nm (closest to 600ish it can get down there) for photosynthesis... relying mostly on Chlorophyll B i would then assume ;)



The original graphs are the best general representation of spectrum needed -

Given that the plant/coral evolved with as much light as needed. <- I think a pretty good standard to go for.

That said compare the individual corals needs to the lights you want to or can offer...


There are even some other theories to deep corals taking advantage of 'less light' than normal corals would - or even just holding onto their zoo-x for some unknown but helpful reason. http://theartfulamoeba.com/2010/11/15/photosynthesis-in-the-deep/
 
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ReeferBatman,
Oh, this is interesting. So, I have LEDs and am looking to get some color back in corals that haven't seemed to like it. Some really do. I have three LEDs

All CREE from their website:
Royal Blue - 450-460 nm
Blue - 465-485 nm
Cool White - 5000-8500 color temp (not sure how this relates to nm)

I've noticed mostly my red sps's bleaching out, couple other corals as well, some seem perfectly fine.

So, I was looking to supplement either with Violet LEDs 410-420 nm, or add 4 48" T5 bulbs over a 180 g (but I don't know which bulbs)

I may try backing down my whites even further in case that's part of the issue, but from many posts I've read it seems LEDs are just missing something. So, I thought T5's might be the way to go, although I've only ever used MH and VHO. But don't want to go back to that, I do like parts of the LEDs.

Which spectrums can T5s benefit most? And when should they be ran in what parts of the day in your opinion? I run my LED's RB first, then some blue, then peak with Whites and ramp down the other way till night.

Andrew
 
LED's offer the entire spectrum - HOWEVER the actual spectrum they give out is entirely dependent on their lenses. Hence one LED light will perform miraculously, while another LED is pure $hit.

Sounds like your missing your upper spectrum, and the Zoo-x is ejecting from the coral in hopes of better territory [more light] somewhere else.

Throw some higher spectrum on there.

Your whites (5000-8500) are in the right spectrum to promote regular [above ground and freshwater] plant photosynthesis, not coral photosynthesis. Replace those with something higher (in Kelvin / nm) like 10,000k t5 or more specified LEDs.


I supplement my 10,000k t5's with LED actinic Blue's for example.

As to your confusion - its easy as light has no real easy to relate measurements...

Kelvin - is color to our eyes.
Nanometers - is the spectrum of energy delivered.
Watts - are merely a human energy consumption measurement - unrelated to
Intensity - amount of energy delivered.

Par value is an attempt to 'morph' all of these into one easily representable graph, but then it doesn't represent every aspect as well... but its the best for our purposes.
 
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OK, I could try that. I have yet to buy the t5 kit so want to make sure that's the way to go. This leads to another question then. When I was running MH and VHO combo I was running a 20K bulb and Atinic VHO's. I was pretty far away from the 10K range under that set up but everything was fine. Thoughts? With 10K blubs I'll be a lot more white looking, I prefer the 20K look so I tried to get LEDs that would model that, but obviously something isn't happy in my tank.
 
the higher Kelvin rating means more blue ... same as the blue represented by the lower nm readings... see how easily it gets confusing?

the 14k and 20k lamps produce enough of the red spectrum to satisfy photosynthetic needs, but not as much of an energy spike where the corals actually need it like a 10,000k bulb would.

AKA 20k looks better (more blue) but 10k offers more light the coral actually needs.

As i said originally, its all a trade off on how it looks to people vs what the corals want.

Go with what works for you :)
 
Makes sense, so the Cool Whites don't hit the 10K range and I dont see any LEDs that really do. So, even cranking them up wont do anything.

If I add T5s which ones would be needed? Again, sorry I'm new to the t5 thing. These are like the day time, second photosynthesis you talk about, correct? So run from say 11am to 3pm type of thing?

All this seems pretty trivial, I'm surprised there aren't LEDs that cover more of the spectrum yet in a better way.
 
I've been reading articles on advanced aquarist and their experiments on light and coral growth.

There's one study from 2008 that shows growth of hard corals correlated worse with increasing red light. And didn't correlate with more blue. 10K bulbs actually did the worse in terms of growth rate and their percentage of red light was the greatest.
http://www.advancedaquarist.com/2008/12/aafeature1


There's another one from 2003 that shows bleaching and poor growth of sps coral with narrow spectrum red led.
http://www.advancedaquarist.com/2003/11/aafeature


This one shows the mitosis of zooxanthellae slows when more red light is added to the light spectrum.
http://www.advancedaquarist.com/2009/5/aafeature/


What I gather from these studies is that more red light inhibits coral growth even if temporarily. Bulbs with 10K actually correlate to the worst growth rate and bulbs 14K to 20K correlate to the best growth rate.

Take it for what that's worth. I've heard so much on these boards that using warmer white bulb helps with growth which is clearly not what these articles and experiments show.

Personally, I'm looking to replace my T5 bulbs with the higher K to see how the corals react and get rid of the reds and 10K's. It'll probably not look aesthetically pleasing, though...
 
re: http://www.advancedaquarist.com/2008/12/aafeature1

They are using Acro which I already posted a graph on. Acro's use less red light than most other corals.

Further experiments (Kinzie and Hunter, 1987) found that corals exposed for more than 60 days to light composed of mostly the red portion of the spectrum resulted in corals that ""¦were almost entirely free of algae and appeared white,

So, when given only red light, the corals recede/die. this is right in line with the previous graphs I posted, you need the blue spectrum in addition to the higher spectrum.

All they really say is if you give a coral only red light, it won't do well. That was already established.

As for too much, we already know that too much and too little light can cause 'bleaching'.

Re:http://www.advancedaquarist.com/2003/11/aafeature

Its an LED comparison from almost a decade ago. I BARELY trust LED's now...

In addition, I suspect his reds had too much intensity causing the bleaching. Just my take though.


Re: http://www.advancedaquarist.com/2009/5/aafeature/

Exposure to only 'red' light significantly inhibits the productive cycle

This we already know, we need a more full spectrum.

However their other insight, that red with the blue limited coral growth is ad-hoc at best, and merely a supposition, it had no data to back it up that was statistically significant.



But I do like these links, I am learning more in the process. This is an open discussion, and I don't have all the answers. Good points made.
 
Makes sense, so the Cool Whites don't hit the 10K range and I dont see any LEDs that really do. So, even cranking them up wont do anything.

If I add T5s which ones would be needed? Again, sorry I'm new to the t5 thing. These are like the day time, second photosynthesis you talk about, correct? So run from say 11am to 3pm type of thing?

All this seems pretty trivial, I'm surprised there aren't LEDs that cover more of the spectrum yet in a better way.

White LEDs will cover a spectrum much like any other white light. What it will lack is the UV and infrared emissions that are inherent to "full spectrum" lighting sources weve used in the past. If you look at a cct of a white Cree LED it looks remarkable similar to other sources in the same Kelvin range. The colored LEDS is where you see a very tight focused light, in regards to nanometer measurements. We are just beginning to learn what combinations will be both aesthetically pleasing and conducive to growth much like the early days of MH or T5. We are also comparing LEDS designed as general house lighting to bulbs that were designed for our tanks hence the need to combine colors to get the look we want.

So long story short you can touch almost any portion you want of the visible spectrum with LEDs. Now if your looking for UV or IR your search may prove more difficult and whether those are necessary is another debate.
 
I'm not really looking for IR or UV per say. I'm just trying to pinpoint the best way to get more specturm in there. Something's missing because some corals just aren't happy with the LEDs. Perhaps its just more tinkering with intensity and # of hrs, but I suspect its a bit more than that from other LED reviews on here. I found a $100 t5 set up so not much to lose adding those in to see if it helps. I'll probably start with 2 attinic type blubs and 2 white ish trying to cover both ends of the spectrum.

Andrew



White LEDs will cover a spectrum much like any other white light. What it will lack is the UV and infrared emissions that are inherent to "full spectrum" lighting sources weve used in the past. If you look at a cct of a white Cree LED it looks remarkable similar to other sources in the same Kelvin range. The colored LEDS is where you see a very tight focused light, in regards to nanometer measurements. We are just beginning to learn what combinations will be both aesthetically pleasing and conducive to growth much like the early days of MH or T5. We are also comparing LEDS designed as general house lighting to bulbs that were designed for our tanks hence the need to combine colors to get the look we want.

So long story short you can touch almost any portion you want of the visible spectrum with LEDs. Now if your looking for UV or IR your search may prove more difficult and whether those are necessary is another debate.
 
Check out the spectrums needed for photosynthesis in corals (different than plants!!!).

Actinics provide the 'starter kick' to prompt phtosythetic activity, but not enough to actually let the photosythetic algae fully produce energy for the coral. You need a much higher peak for that, 10,000k lights will do it.

The Purple lights contain the same actinic spectrum as the true blue actinics but also provide some additional higher spectrum lighting. Still, I wouldn't rely on it solo for actual good coral growth, but if you already have your 10,000k spectrum covered you can swap or add a purple with no detriment. It's really just how you want it to look.


Ramdude - if you truly want to accelerate coral growth, replace a blue w/ a 10,000k. Truth be told you could even run 3 10k - 1 blue/purple for best growth rates. Your current setup minimizes the hump of spectrum that coral photosynthesis fully needs while instead them look friggen awesome instead with your 3 blues... It's a trade-off.

Tommy - The Purple lights do throw off a limited amount of the higher spectrum light needed but not enough to fulfill growth potential of the corals.

Throwing mostly Blue and Purple bulbs over your tank is like Having a supermodel girlfriend you only feed bread... She looks great, but your kinda starving her...

not disputing that...but back before the proliferation of T5 colors, many of us used plain ole 5000-6500K's and corals grew pretty decent ( alil brown but decent)...
just thought I'd mention it
 
I'm not really looking for IR or UV per say. I'm just trying to pinpoint the best way to get more specturm in there. Something's missing because some corals just aren't happy with the LEDs. Perhaps its just more tinkering with intensity and # of hrs, but I suspect its a bit more than that from other LED reviews on here. I found a $100 t5 set up so not much to lose adding those in to see if it helps. I'll probably start with 2 attinic type blubs and 2 white ish trying to cover both ends of the spectrum.

Andrew

I was just trying to clarify that the set of LEDs specific to any one fixture may be missing parts of the spectrum but that LED technology has the capability to hit all parts of the visible spectrum. T5's would be an easy way to cover areas you feel are lacking.
 
LED's offer the entire spectrum - HOWEVER the actual spectrum they give out is entirely dependent on their lenses. Hence one LED light will perform miraculously, while another LED is pure $hit.

Bear in mind Its early Sunday morning and I've had a few, however... If I understand what you are claiming here the spectrum of an LED varies dependent upon the lens?

Unless the lens employs a dichroic filter(which would be highly irregular) I find this hard to believe. The spectrum of an LED depends upon the type of semiconductor material and/or phosphor. The lens only determines the angle of focus.

My understanding is that the red light is mostly filtered out in the first 10 meters or so. This is consitant with my very limited diving experience. I'll eat my virtual hat if I'm wrong on this.
 
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