Ratios

[Nightstar]

Well now... I see we skipped over the whole lime is white without the blue debate and have gone down the white LED kills acropora rabbit-hole.

 

I don't keep acorpora. I've tried but they have died. They died under fluorescent, MH and LED. I blame my lemonpeel angel and my flavicauda before him.

 

Just to be clear is it cool white, neutral white, warm white or some other white that kills those acros dead? Is it any of those from Cree, Phillips or some other company or all of them(even though they all have different spectral output). There must be an answer to this plague on the poor acros!

 

BTW my porites is growing well under LED including a healthy dose of warm white(CREE XTE 2700k) which comprises about 17% of my total lighting output. I guess porites is immune to the evils of acro killing white LED. Lucky me.

[Horerczy]

Let me sum up what I took from Markalot's posts.

 

Basically because leds behave in a completely different manner from mercury based lighting (mercury is what creates the massive green spike in halides and fluorescent fixtures) the perceived brightness doesn't match up to what users are used to.

 

Because of this they turn the lights up brighter than they realize and cook the corals.

[markalot]

Let me sum up what I took from Markalot's posts.

 

Basically because leds behave in a completely different manner from mercury based lighting (mercury is what creates the massive green spike in halides and fluorescent fixtures) the perceived brightness doesn't match up to what users are used to.

 

Because of this they turn the lights up brighter than they realize and cook the corals.

 

Yes.

 

It's interesting that Lime is white without the blue ... I wish I had a spectrometer so I could see what I was putting into the tank and why some combinations work and some don't. My theory is that using enough LED's to get the tank bright to the eyes is dumping way too much light and killing corals. I actually was thinking it was energy above 550 but Lime brings along plenty of this, though perhaps less than warm white does. There are also early LED adopters using just blue and cool white LED's that had coloration issues but did not kill acros. This is a good example, very cheap LED's and didn't have any lighting issues with this tank or his next one.

 

http://www.reefcentral.com/forums/showthread.php?t=2231494

 

You can see the issues with some acros though, especially the red planet. This is why warm was added to the mix, to try and bring out the reds.

[theatrus]

I really should finish up my board for these micro-spectrometers I was working on. They're expensive little units (~$200 a pop for the sensor head) and not super high resolution (8-15nm) but it would answer a lot of questions

 

( https://www.hamamatsu.com/jp/en/C12666MA.htmlis the sensor, company is not very easy to work with though I should have a shipment coming in from Japan in the next month or so for a few of them )

[jedimasterben]

 

Yes.

 

It's interesting that Lime is white without the blue ... I wish I had a spectrometer so I could see what I was putting into the tank and why some combinations work and some don't. My theory is that using enough LED's to get the tank bright to the eyes is dumping way too much light and killing corals. I actually was thinking it was energy above 550 but Lime brings along plenty of this, though perhaps less than warm white does. There are also early LED adopters using just blue and cool white LED's that had coloration issues but did not kill acros. This is a good example, very cheap LED's and didn't have any lighting issues with this tank or his next one.

 

http://www.reefcentral.com/forums/showthread.php?t=2231494

 

You can see the issues with some acros though, especially the red planet. This is why warm was added to the mix, to try and bring out the reds.

Actually, blue photons have much higher energy levels than green and red. A 450nm blue photon is around 2.76eV, a 565nm green (like lime's peak) is 2.2eV, and a 660nm red photon is 1.88eV. This is all a moot point, though, as a single photon of any wavelength gives the same amount of energy to the photosynthetic process.

[markalot]

Actually, blue photons have much higher energy levels than green and red. A 450nm blue photon is around 2.76eV, a 565nm green (like lime's peak) is 2.2eV, and a 660nm red photon is 1.88eV. This is all a moot point, though, as a single photon of any wavelength gives the same amount of energy to the photosynthetic process.

 

But what does energy even mean anyway, my terms are all amateurish due on my limited knowledge.

 

Someone did experiments with just blue light and could not kill corals. They also blasted them with red and killed a bunch but I'm not so sure just blasting a coral with red light is telling us anything other than "don't do that".

 

Taking my silly theory a step further, cool white LED's are brighter to the eye than warm white, so I wonder if the introduction of warm white is what started the problems? (I understand not all of you think there is a problem).

[KnH]

My local club has a par meter that they loan out, LEDs can be tough to get an accurate reading, but it gives you a starting point

A dimming driver is a life saver, start low and ramp up and more is not always better.

 

In the end, it comes down to each of us paying attention what goes on in our tanks; our eyes are very poor at gauging light intensity

 

With WH & T-5s companies did the testing and engineering, LED recipes are a work in progress; sometimes it is just let's see what works and HOPE we can get it right. It is easier to blame "White" LEDs than trashing what you have and starting over

 

A bad LED mix is just a bad choice that has negative consequences

 

http://www.advancedaquarist.com/blog/red-light-negatively-affects-health-of-stony-coral

"Note: red light is commonly found in proven lights such as Radium metal halides and numerous fluorescent bulbs as well as in wild reefs, so the idea is not that red light is necessarily harmful but that too much red light can have negative effects on how stony corals regulate photosynthesis."

 

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

"narrow bandwidth light sources."

[jedimasterben]

But what does energy even mean anyway, my terms are all amateurish due on my limited knowledge.

 

Someone did experiments with just blue light and could not kill corals. They also blasted them with red and killed a bunch but I'm not so sure just blasting a coral with red light is telling us anything other than "don't do that".

 

Taking my silly theory a step further, cool white LED's are brighter to the eye than warm white, so I wonder if the introduction of warm white is what started the problems? (I understand not all of you think there is a problem).

Energy in electronvolts is the absolute amount of, well, energy that a photon has. It's not the easiest to explain because it deals with the individual photons directly, but what we want is the amount of PAR in micromoles per square meter (which is equal to 6.022 x 10¹⁷​ photons, since one micromole is equal to 1 mole x 10^​-6), and for that measurement, the photons are not weighted according to their energy levels, as a high energy blue photon does the same amount of 'work' that a lower energy red photon does in the photosynthetic process.

 

Yes, Dana Riddle did an 'experiment' with red light and so did Tim Wijgerde, but using 128/256 PAR of solely 660nm light is just absurd and I've criticized both articles for grasping at straws for their conclusions from these unrealistic experiments (though Tim's paper did not come up with this conclusion, it was invented by Leonard Ho at Advanced Aquarist).

 

Cool white LEDs are mostly blue in output (especially the high CCT, low CRI cool whites used in almost all commercial LED fixtures), yet have higher to significantly higher luminous flux output, but even so they should technically be more dim to the eye since the ratio of blue to green/red is higher.

[DaveFason]

A few things to state in this debacle

 

Mark - Remember you are using a LED without optics. 99% of other manufactures use secondary optics creating another variable.

 

Here is a great read on the PAR readings in water.

https://reefbuilders.com/2016/08/26/underwater-par-measurement-is-strongly-impacted-by-immersion-effect/

 

Looks like Apogee had to go back to the drawing boards due to us using in water!

 

-Dave

[markalot]

A few things to state in this debacle

 

Mark - Remember you are using a LED without optics. 99% of other manufactures use secondary optics creating another variable.

 

Here is a great read on the PAR readings in water.

https://reefbuilders.com/2016/08/26/underwater-par-measurement-is-strongly-impacted-by-immersion-effect/

 

Looks like Apogee had to go back to the drawing boards due to us using in water!

 

-Dave

 

Isn't that interesting. I have the old one so for me it's a minor 7% correction, not the whopping 32%!

[Nano sapiens]

 

Isn't that interesting. I have the old one so for me it's a minor 7% correction, not the whopping 32%!

 

I believe the correction factor of 1.07 for the MQ-200 sensor used underwater is in addition to the compensation factor one uses to account for the relatively heavy blue/violet lighting we typically use in reef tanks.