With PAR being equal will white light grow coral faster than blue light?

[Wiskey]

Hello all!

I know that you need allot more blue light than white light to make the PAR numbers equal, but let's say that you have 2 sides to your tank. One side used all white T5 bulbs, and the other used all Blue Plus. If you had enough T5 bulbs on the blue side so that the par was equal, would the Acros grow at the same rate on both sides?

Thank you!
Whiskey

 

[Nano sapiens]

Hello all!

I know that you need allot more blue light than white light to make the PAR numbers equal, but let's say that you have 2 sides to your tank. One side used all white T5 bulbs, and the other used all Blue Plus. If you had enough T5 bulbs on the blue side so that the par was equal, would the Acros grow at the same rate on both sides?

Thank you!
Whiskey

It's not really about PAR (Photosynthetically Active Radiation), but about PUR (Photosynthetically Usable Radiation). If you were to try and have equal PAR on both the white and blue sides, you'd be supplying much more PUR on the blue side.

PUR consists of the light wavelengths that corals can use for photosynthesis (violet to blue and red wavelengths). PAR consists of all wavelengths of visible light between 400nm and 700 nm, whether corals can make use of them, or not.

We use PAR only because if can be measured rather inexpensively. PUR measurement requires an expensive spectrometer to measure the individual spectra.

 

[Wiskey]

If you were to try and have equal PAR on both the white and blue sides, you'd be supplying much more PUR on the blue side.

Does that mean that the coral would grow faster on the blue side?

The reason I'm asking is growth is important to me right now. I have a T5 fixture that is not quite enough light for good growth and I'd like to supplement. I'm considering blue LED's or White Led's. If I can just use more light that's a bit bluer (like more blue+ tubes) then I would prefer that, but if the 6500k or 10,000k spectrums provide more growth regardless of how much blue you have then I would go that route.

Thank you!
Whiskey

 

[Reefvet]

Historically the most effective light for growing corals was the Iwasaki 6500K (daylight) MH. I ran them 20 years ago with Actinic VHO supplementation. It was a really popular combo.

Having said that, Nano's reply is accurate but it's only part of the story.

But let's back up first.

What bulbs are you running and what are you trying to grow ?

 

[Ink]

It's not really about PAR (Photosynthetically Active Radiation), but about PUR (Photosynthetically Usable Radiation). If you were to try and have equal PAR on both the white and blue sides, you'd be supplying much more PUR on the blue side.

so why coral calcification is higher with "white" light? That's my univocal experience in 16 years with MH and T5 on SPS.

I think the answer can be found some Dana Riddle AAOL articles...

Luca

 

[Wazzel]

Does that mean that the coral would grow faster on the blue side?

The reason I'm asking is growth is important to me right now. I have a T5 fixture that is not quite enough light for good growth and I'd like to supplement. I'm considering blue LED's or White Led's. If I can just use more light that's a bit bluer (like more blue+ tubes) then I would prefer that, but if the 6500k or 10,000k spectrums provide more growth regardless of how much blue you have then I would go that route.

Thank you!
Whiskey

Lower K lamps grow corals faster, but they do not look as good.

 

[Wiskey]

What bulbs are you running and what are you trying to grow ?

I have a 75G tank with a 4x54W Tek T5 retro setup. I was hoping it would be enough, but I was wrong, my PAR is ~280 at the top, and ~180 at the bottom.

I have 2 Guiesman atinic blue bulbs, one Guiesman purple plus, and one ATI Coral +.

I'm trying to grow SPS and Clams. Right now the tank is mostly frags, my color is fantastic! And growth is slow and steady, but my tank with XM10K's grew corals much faster.

Whiskey

 

[Wiskey]

Historically the most effective light for growing corals was the Iwasaki 6500K (daylight) MH. I ran them 20 years ago with Actinic VHO supplementation. It was a really popular combo.

Having said that, Nano's reply is accurate but it's only part of the story.

But let's back up first.

What bulbs are you running and what are you trying to grow ?

so why coral calcification is higher with "white" light? That's my univocal experience in 16 years with MH and T5 on SPS.

I think the answer can be found some Dana Riddle AAOL articles...

Luca

Lower K lamps grow corals faster, but they do not look as good.

So it's true then? It has nothing to do with the amount of light and everything to do with the spectrum of light? 6500K and 10,000K bulbs simply grow corals faster than these new blue Coral+ bulbs and such?

Does anyone know why this is?

Whiskey

 

[Nano sapiens]

so why coral calcification is higher with "white" light? That's my univocal experience in 16 years with MH and T5 on SPS.

I think the answer can be found some Dana Riddle AAOL articles...

Luca

My take on this question...

Most of the corals kept by reefers are collected from shallower water. Most coral collectors collect in easy access areas and don't use scuba, so depth of collection is typically limited to very shallow up to free-diving limits. These corals are adapted to a warmer spectrum more similar to 6500K, but many can also adapt well to higher kelvin lighting.

If one looks at the area of greatest coral abundance, the depth is around 18m - 27m. That's quite deep for free-diving, so I would say that the majority of our corals do not come from such depths where the light field is more 'blue'. If one were to collect exclusively from these depths (or deeper), it is quite likely that those corals would do better under higher kelvin lighting.

 

[Nano sapiens]

Just to throw some fuel on the fire from one of Dana Riddle's latest aricles:

http://www.advancedaquarist.com/2015/4/corals



'For this particular coral (Porites lobata), the spectrum was not found to matter much:

Figure 15 shows the average weight gain of the 4 groups (n = 10 each.)

Figure 15. There was no significant difference among growth rates.

Conclusion and Discussion
All LED luminaires promoted coral growth over the course of the 75 day procedure and although there were differences, they were not statistically significant.'

 

[Ink]

http://www.advancedaquarist.com/2014/5/aafeature

I think here is the answer.

IMO corals are simply adapted to a specific spectrum, so they can hardly tolerate a suddenly increased red radiation. They need time to adapt. This is why deep water acro are harder to be adapted into shallow water reef tank.
Anyway red and UV light is more efficient than blue (but not controllable) promoting photosynthesis.
It is very important to avoid nitrogen deficiency in order to avoid harm to the corals.
Light must be always in balance with alkalinity and nitrogen availability (more light and more alk, need much nitrogen - look for DIC limitation in stylo recent article, always by Dana Riddle).

Luca

 

[Wiskey]

I read both the articles.

One seems to indicate that spectrum has no effect on growth speed with par held constant.

The other seems to indicate that blue is a less efficient spectrum for coral use.

My question though is:
If we provided as much blue light as we wanted, if power were no consideration, and heat was not a problem,.. could we get the same growth rates with 20K or even pure atinic blue lamps that we can get with XM10K or 6700K MH lamps?

Thank you,
Whiskey

 

[Wazzel]

Not sure, it is my understanding that corals need a broader band of spectrum than just blue. It is why RGB LEDs perform poorly while units that had broad spectrum white do well. Most corals are in water depths that still have a wide bands of light available to them, even the one's in "deep water". Tubes may have enough of those other spectrum to be able to do ok, but I have not look at a spectral plot.

 

[Wiskey]

Not sure, it is my understanding that corals need a broader band of spectrum than just blue. It is why RGB LEDs perform poorly while units that had broad spectrum white do well. Most corals are in water depths that still have a wide bands of light available to them, even the one's in "deep water". Tubes may have enough of those other spectrum to be able to do ok, but I have not look at a spectral plot.

Interesting thought!

So,.. Since my Coral+ is about 15K, and my Atinic blues, and purple plus fill in pinkish and blue gaps, then if I get a LED with 10K and 460 to supplement with I'll be wideing the band of light I'm providing and hopefully making my light more versatile.

Makes me think that would be a better move than getting another LED purely in the Atinic blue spectrum.

Whiskey

 

[Reefvet]

I have 2 Guiesman atinic blue bulbs, one Guiesman purple plus, and one ATI Coral +.

I'm trying to grow SPS and Clams. Right now the tank is mostly frags, my color is fantastic! And growth is slow and steady, but my tank with XM10K's grew corals much faster.

So you've got great color. That's the one thing so many struggle to achieve.

IF you want to try and get faster growth change one of the actinic and the purple plus out for ATI's Aquablue Special. It's their highest PAR bulb, still has a lot of added blue in it but it's a full spectrum bulb.

I ran a lot of XM's, still have a few out in the garage. They did grow great corals but I don't miss the heat or the electric bill.

I have a TEK 4X39 on a 40B with 1 coral +, 2 blue + and a purple +. I get 350 par on the sand. T5s to the sand is 20". SPS have good color and grow very fast.

I have another identical setup with 2 Reefbrite blue strips on one side of the TEK and 3 Kessil A150s on the other side. 2 are Ocean blue and 1 is Deep Ocean blue (actinic). Par is 550 on the sand.

 

[Wiskey]

ReefVet:
I will look into the Aquablue Special, I could swap the purple for my other Coral plus today. Would that help? It's 40% Aquablue Special, and 50% blue plus according to ATI. I really should get out my PAR meter and measure each tube.

I don't miss the MH heat either I must say.

This was my PAR with this bulb combo:
ATI True Atinic
ATI Coral+
ATI Coral+
ATI True Atinic

PAR by Wiskey2727, on Flickr

As soon as I saw those numbers I switched to what I have now:
Guiesman Atinic Blue
ATI Coral+
Guiesman Purple+
Guiesman Atinic Blue

I don't have PAR numbers for the new bulbs but it is a little higher.

This is what my green slimer did in about a month and a half, it's even better now:
Day I got it:
IMG_4710 by Wiskey2727, on Flickr

~Month and a half later:
GreenSlimer by Wiskey2727, on Flickr

You can see the color, and it is growing, but just not quite as fast as it can, the Green slimer is a very fast grower. My other corals are simalar, they color up amazing but growth is very slow.

I ordered some 10K and Atinic blue LED's to put right in the middle of my T5's, I figure this will give me more light, and a wider spectrum at the same time. I will start with 12 3W LED's in 4 groups over the tank (1 blue flanked by 2 whites) then redo my PAR numbers and go from there.

Thank you!
Whiskey

 

[Mock]

White light for growth, blue light for color.....

 

[shih87]

....

~Month and a half later:

.....

Nice grow!:thumbsup:

 

[kevin_e]

It's not really about PAR (Photosynthetically Active Radiation), but about PUR (Photosynthetically Usable Radiation). If you were to try and have equal PAR on both the white and blue sides, you'd be supplying much more PUR on the blue side.

PUR consists of the light wavelengths that corals can use for photosynthesis (violet to blue and red wavelengths). PAR consists of all wavelengths of visible light between 400nm and 700 nm, whether corals can make use of them, or not.

We use PAR only because if can be measured rather inexpensively. PUR measurement requires an expensive spectrometer to measure the individual spectra.

Is this true? Most publications will state that a Iwasaki 6500K is best grow lamp for coral (we don't use it because it's yellow).

 

[Nano sapiens]

Is this true?

Most publications will state that a Iwasaki 6500K is best grow lamp for coral (we don't use it because it's yellow).

Yes.

However, just because a particular light source puts out more PUR than another doesn't necessarily mean that it is 'better' for coral growth. A 'complete spectrum' light source where the intensity and ratio of the wavelengths mimics the depth that the corals grow best at would likely be optimal for coral growth. Superior coloration may require a different spectrum than what is needed for optimal growth (depending on coral type/genus/species/morph).

The Iwasaki 6500K mimics the light spectrum for shallower water and is where most of the corals that most people keep come from (especially true in the past as deeper water corals, such as Leptoseris, were relatively rare).