Is white light necessary in a reef?

[Shawn]

The title says it all - well, most of it.

I've got a BioCube32 with the stock lights upgraded to Steve's LEDs. These lights are great, but there's no control of red/green spectrums, just blue and white.

My question - is white light necessary at all in a reef tank? I've got almost 50 kinds of corals, mostly LPS and softies/zoas/shrooms. I've got an anemone as well. What do y'all think? Can I run blues all the time?

 

[FutureInterest]

I've been told that corals have evolved to mostly just utilize the wavelengths that penetrate the water the best which makes sense. I only use the blues and uvs on my radions these days. The t5s still provide other wavelengths though...

 

[hankhill31]

The title says it all - well, most of it.

I've got a BioCube32 with the stock lights upgraded to Steve's LEDs. These lights are great, but there's no control of red/green spectrums, just blue and white.

My question - is white light necessary at all in a reef tank? I've got almost 50 kinds of corals, mostly LPS and softies/zoas/shrooms. I've got an anemone as well. What do y'all think? Can I run blues all the time?

I use only blues now


Sent from my iPhone using Tapatalk

 

[Shawn]

Good to know. I’ve been running blues for weeks now and I wanted to see if it would have an adverse affect. Seems like I’ll be fine

 

[ichthyoid]

We might want to consider the several things going on with light in seawater. Among them are -
-the transmission spectra of seawater (above)
-the absorption spectra of the various pigments within the zooxanthellae (symbiotic algae) living within the coral's tissue (below)
-the light sensitivity of the human eye over the visible spectrum (also below)

Only when we consider the effects of all three, do we get an idea of the effects on our corals versus our eye's perception of the light we have produced.
In short, our corals do not respond to light the way our eyes do.
This is compounded by the way seawater transmits visible light.
The effect of running all actinic (~420nM/blue) lights produces a lot of fluorescent 'pop', at the cost of appearing as artificial, imho.
As long as your corals get what they require, the rest is personal preference.
Just know that the blue in the tank is actually much brighter in reality than our eyes can perceive.

 

[york1]

I have the same setup on my biocube. I run about 10% on my whites because I like the way it looks. My rockwork is 90% covered with zoas, palys, and shrooms. I also have a couple of acans on the sandbed that are doing well

 

[Steve Burton]

I look forward to hear what Dana Riddle has to say at the Expo.

 

[Mom2Many]

I run my blues on my tanks between 80 and 100 percent and my whites between 40 and 60 percent and everything does very well. I could probebly go way less with the whites but like some white because I like how it looks.

 

[enderg60]

In general, softies and LPS will do fine with not much, or no whites, because they grow deeper. SPS will need more of a full spectrum since they tend to grow in the top 20ft. Ive seen plenty of softie tanks running only actinics doing just fine, but with growth a bit slower than normal.

Personally I hate the totally unnatural look of all blue.

 

[Eric_n_Ga]

Anyone still running just blues with success ?

 

[Doberman13]

I actually prefer more blue lights over whites. For the longest time I was running just blues from my Aquaknight light. When I got the noopsyche I set it up to peak at 1% whites. It seems like my tank is loving it.

 

[Eric_n_Ga]

Funny that's where I keep my white is near 4%

 

[kullas]

I run all blues on my setup. After reading this thread I decided to try the whites at 5% and I will see how they go. With all blues and uv i was seeing good growth on everything, monti's, stylo's and such the only thing I'm not seeing alot of growth on is my birds nest. Maybe adding some white lite will add growth to the birds nest.

 

[Eric_n_Ga]

I started running little to no white in June of last year to battle algae , never turn the whites back on. Now they are slightly on between 5 and 9pm

 

[dball711]

ZERO whites here, great color and really good growth. I see higher PUR values with no whites, more usable PAR. I've been focused on th spectrum from 400-500nm, plus maxing out UV on my LED fixtures.

Whites are really a personal preference, the corals don't need them to survive or thrive.

 

[bigd]

ZERO whites here, great color and really good growth. I see higher PUR values with no whites, more usable PAR. I've been focused on th spectrum from 400-500nm, plus maxing out UV on my LED fixtures.

Whites are really a personal preference, the corals don't need them to survive or thrive.

Well, there you go! Looks like I’ll be cutting my whites down based off the Sanseis input!

How about reds and greens Dave? I’d love to see what you’re running your G5 Blues at schedule wise!

 

[ActiveAngel]

Not sure if it’s possible to have higher PUR output without whites, all els being equal. I suspect something else must be going on (like turning off blues) to get a lesser number. This is because PUR and PAR are a measure of photon quantity. if a person turns on a light, it doesn’t make things darker. This should be true with LEDs. To my understanding: More light = more light... but I could be wrong. Not sarcastic.

That said. I agree that corals in reef tanks can survive with solely a nice spectrum of blue light (I.e. none or minimum whites). For me, I prefer to have my whites on during the day, In order to provide some spectrum variety for any organisms that need it. ... and then blues in the evening during sunset.

 

[dball711]

As a point of reference...
PAR = measure of the active radiation (light power)
PUR = measure of the usable radiation (is the part of the PAR spectrum used by photosynthetic cells)

Less PUR is available in white lights. Taking a measurement (PAR/PUR) with just blue light produces PAR @ 1215 PUR at 78%. Now add white to the spectrum and PAR goes up to 1333, PUR drops to 76%. See the charts below...

All Blue, no whites.


Same Blue level but added 100% white (Radion gen 5 x15 blue)

Granted this is minuscule overall but know I'm using a Radion Gen 5 x15 Blue (very little white light available).

Now just for some comparison between all blue and full spectrum lighting.

Here's a mostly white in appearance full spectrum light reading. High PAR with lower PUR.


Here is a reading from a very small Reef Brite fixture. Lower PAR but PUR is at 84%.


My point is that White light can dilute the PUR value of a PAR reading and that PAR readings are relative to PUR values. SO when we hear some one is blasting an Acro with 550 PAR and no reference to PUR can be misleading given the example above if there is a 30% variance in PUR.

 

[ActiveAngel]

Oh, I see the miscommunication. You’re relaying the reading off the interface; which isn’t actually PUR even though it’s labeled as such.

PAR and PUR are measured in Micro-moles of photons per meter squared per second. Essentially this is “quantity per area per time”. If area and time are not changed, and any additional wavelengths are added, then PAR and PUR will either increase or remain the same. But they cannot decrease unless light is reduced; that is a requirement for a decrease.

What your interface is showing as PUR must be a ratio... perhaps PUR/PAR. This would make sense to decrease if you are adding any radiation that is not being used. However this ratio is misleading, if you were using it to determine if adding white light is beneficial. Even if white light is beneficial, but a portion of it is not being used, it can show a decreased percentage. The usefulness of this as a percentage is for determining the best bang for your buck in terms of energy usage to power your light.

 

[ActiveAngel]

Just to be clear, it’s the interface that is misleading... not you. Lol

To elaborate a bit, if we compare 1 PAR of blue light at 100% vs 300 PAR of white light at 80% PUR. Then the white light would grow corals better because it’s PUR is higher, even though it’s PUR/PAR ratio is lower.

*assuming that’s what the given percentage is defined as.