Lighting... do you think we OVERDO it?

[janos]

@jda is right somehow 20 years ago i was happy with my 175w Iwaki MH and corals was groin was nice (to my eye) than i jump to the LED mania build lot of DIY LED spend lot of money on tax and border tax,because in Canada you could not buy staff like in the US. After a time bought expensive original factory build LED i still was not happy,and corals was not happy.Someone told me you need different type of LED so i went to buy more expensive LED from different company.Same thing was not happy and corals was not happy.No i back to HO T5 am almost happy but still think about the good old MH it was simple and give something to the corals what they need.

 

[Gregg @ ADP]

Haven’t read the whole thread yet, but for mixed reefs, I like to only have moderately to very intense white for maybe 3-4 hrs/day.

And even then, I like to create some sharp dips (across the spectrum) for 15min or so maybe 3-4x in that span. Corals of all types seem to respond well.

 

[ZoWhat]

I was thinking about this thread yesterday after reading it the first time, and I sort of wonder why reef tank lighting isn't based on ocean depths.

OP here.

OMG! You just nailed what I wanted to ask but you worded it in a different way.

My thoughts exactly....

Why don't hugely popular LED light Mfgrs have different PRESETS for different depths. I.E. Preset#1 = 3-10ft down in the reef water. Preset#5 = 50ft down in the reef water.

But add a 420-460nm spectrum to get that'll florescent POP to a corals look

A Preset sets NM-color-balance for blues thru reds .... & PAR (brightness)

 

[W1ngz]

OMG! You just nailed what I wanted to ask but you worded it in a different way.

I really don't want to name drop, but I think this is what Kessil tries to do. In effect their intensity adjustment adjusts for 'depth' and the limited spectrum adjustments allow that you can adjust things visually within normal light spectrums found on reefs. LED makers that include red LEDs completely confuse me, since red light is entirely dissipated 50' below the surface which is well within even beginner depths for scuba diving. Most acropora grow naturally at depths of 5 to 20 meters. Why not just split it right in the middle, and target spectrum that occurs naturally at ~10m/33ft, the same way we do targeting most water parameters for NSW?

I'll be hypocritical though and also say that I won't give up my actinics. When you're 40' underwater, a natural reef has absolutely no pop or phosphorescence whatsoever. It's mostly just varying shades of browns and greens under purely natural light.

As to the above comments about collecting inverts and fish at freediving or snorkelling depths, I'm unaware of any that are photosynthetic. Light has nothing at all to do with them.

 

[Hermie]

Why don't corals flouresce at depths? is it because the specific blue wavelength isn't "isolated" enough from other hues?

 

[W1ngz]

Why don't corals flouresce at depths? is it because the blue isn't "isolated" enough from other hues?

It gets washed out by the rest of the blue spectrum. The reason artificial actinic lights work is because the intensity of the 420nm range is higher than the visible blue spectrum.

 

[Hermie]

It gets washed out by the rest of the blue spectrum. The reason artificial actinic lights work is because the intensity of the 420nm range is higher than the visible blue spectrum.

makes sense, so even though a 450nm LED produces more 450 than 420nm, its still isolated in the fluorescent range than the ocean

 

[vanpire]

Totally agree. The saltwater filters out certain color spectrums as charted below

My contention is ppl OVERDO the yellow and reds in the form a WHITE light in their tanks.

I'm not looking to be right, just want an open discussion thread

Oh where art thou? Master of Light? @Dana Riddle

Mr. Dana Riddle so smart that before God created light in the beginning, God talked to Dana for his thoughts....


.

According to the graph, at 30 meters, there is still lots of red, yellows, greens, etc. 30 meters is about 100 feet deep. I dive a lot in the Soith Pacific and there’s not a lot of SPS at 100 ft. 90% of the SPS from the places I dived are 10 feet to 50 feet deep, closer to 10 feet. Some places. I could only snorkel because the corals are are just a few feet below me. On the deeper dives, it is the see larger fish like hammerhead sharks, Sunfish (Nolas), etc. You don’t dive deep to see corals.

 

[Hermie]

According to the graph, at 30 meters, there is still lots of red, yellows, greens, etc. 30 meters is about 100 feet deep. I dive a lot in the Soith Pacific and there’s not a lot of SPS at 100 ft. 90% of the SPS from the places I dived are 10 feet to 50 feet deep, closer to 10 feet. Some places. I could only snorkel because the corals are are just a few feet below me. On the deeper dives, it is the see larger fish like hammerhead sharks, Sunfish (Nolas), etc. You don’t dive deep to see corals.

still, that graph doesn't show the gradient of penetration per wavelength

 

[lavoisier]

I'm probably just an old fogie, but I love my 20k, 400w MH and my corals have seemed to like them as well.

 

[fredk]

Spectral quality and light intensity cannot be examined and reported independently with much success. Excessive red light will reduce zooxanthellae density/chlorophyll content. Excessive blue light induces the protective xanthophyll cycle (which shunts blue light away from Photosystem II.) Same for many chromoproteins and fluorescent proteins. The Advanced Aquarist site is down at present. Once it's up, I'll send a link examining spectral quality/intensity on growth rates of the stony coral Porites.

Thanks for the reply Dana. My post was poorly phrased. I have read pretty much all you have written on the subject several times over.

I do understand we know the effects of certain spectrums on some systems in corals, such as the production of protective pigments and red light and the triggering of the photo inhibition, but I don't think we are even close to being able to make a definitive statement on the overall quality of light reaching a given coral.

That specifically relates to the OPs topic. What we perceive as white can be made up of very different spectra. There is an online vendor that provides an "ocean coral white" LED made up of Cyan, red and blue, so a very incomplete spectrum, yet it looks white to us.

So which "too much white" are we talking about? Is it 6500K white as one poster suggested? We know that lights with very different spectal output can have the same Kelvin rating. Now the question is about which 6500K light we are talking about? If it is 6500K white, why was (and still is?) the Iwasaki 6500K the best Halide for growing corals?

For those corals that were negatively affected by too much light in a given aquarium, were there other deficiencies, like missing nutrients, fluctuating or incorrect alkalinity, poor flow...?

We know that corals do not get 100% of their nutrition from sunlight. What is the relationship between nutritional health and light?

I also recall you writing about different clades of zooxanthellae having different absorption spectra and that a given coral may recruit different clades at settlement. How does this affect what is the 'best spectrum of light" for that coral?

Lastly, I want to turn to human nutrition and health as an analogy why we should be cautious about the specific makeup of light and coral health. In an interview, a food scientist, one of the people who does primary research on human nutrition had this to say about the 'best' diet: "Eat unprocessed food, mostly vegetables, and lots of raw foods." Why was his recommendation so generalized? Because, after decades of research and billions spent, we still know very little about human nutrition and health.

Think about how much less we know about overall coral nutrition and health let alone the specific topic of the quality of light.

My own personal feeling is that we spend too much time "in the weeds" on the details of lighting and not enough time on the overall conditions in the tanks we keep our corals in.

P.S. My apologies if this turned into a bit of a rant. I strongly believe this is a much more complex topic than we think it is.

 

[bacc2bacc]

Blue spectrum is the way to go, I rarely run any whites and if I do it’s minimal for the day maybe 2 hours max

 

[fredk]

The only way that I know how to even get close to finding about good quality is to use a bunch of different lights for a decade, or more, and observe for yourself... or to look at the long term results of very experienced people with your own eyes (photos do not do it right).

I know that the sun is good quality because I believe in the Scientific Method where nature is the best until proven otherwise. From there... it gets fuzzy... but with enough experience, it is easy enough to tell that some lights do certain things differently.

I agree. So when things get different, how do we know that different is better or worse? How to we know what it is about that different that is good or bad.

I wish I was 20 again when I knew so much more. ;Shy

 

[fredk]

Not too many people would want their tank to look like the ocean where the stuff in your tank is collected.

...

The bottom line is that nearly everything in your tank (and possibly everything without the "nearly") was originally collected under the equivalent of a 6500k MH or T5 bulb in nature. ...so natural is not what people are after.

I think this is the best post in this thread. The colours you see on the reef vary a lot by depth. At three meters the colours are stunning, but also very much 6500K full spectrum. At 30 meters (90ft) its all an ugly bluish grey.

At 12 to 15 meters where most of the corals seemed to be, there was a slight bluish tint, but nothing like the blue you see with a 20K halide or LED setup. I never saw any coral fluorescence or bright coral pigments at this depth. That was probably because of: too much other light masking fluorescence, not enough light to trigger the development of protective pigments.

The only place I saw a brightly coloured coral was off Hinchinbrook Island in rather murky water. It was a Montipora digitata in about a foot of water at close to high tide.

I personally think the bright colours in corals we like so much has more to do with very high light conditions and the 'sunscreen' pigments corals produce, a stress reaction, than it does with overall coral health.

 

[Phycodurus]

i’m geeking out over this discussion haha ... always been fascinated by light and it’s complex properties & how it’s utilized in the biosphere: spectra, lux, PAR, photosynthesis, lumens, kelvin ratings, etc, etc.

i dare say i’m in the wrong career (as i respectfully tip my hat to dana and his colleagues)


(^__^)v

 

[fredk]

still, that graph doesn't show the gradient of penetration per wavelength

Exactly. On more detailed charts you can see that there is no, or very little, red light. The light at 30 meters is just plain ugly!

 

[fredk]

One last observation. When I first got into this hobby, I had the good fortune to belong to a club that had a copy of Veron's Corals of Australasia and the Indo-Pacific. I spent may hours reading and re-reading much of it.

In species descriptions he would note where on the reef a coral was most often found. In some cases, like Cynarina it was strictly deep water. Others were mostly in one zone, but occasionally in others. Some were broadly distributed from the fore reef, to the reef crest, to the lagoon. Talk about a broad range of lighting conditions for that last one!

 

[Dana Riddle]

Here's a chart showing spectra transmission in the 'clearest' seawater (Jerlov Type I Oceanic) at 1 and 10 meters.

Thanks for the reply Dana. My post was poorly phrased. I have read pretty much all you have written on the subject several times over.

I do understand we know the effects of certain spectrums on some systems in corals, such as the production of protective pigments and red light and the triggering of the photo inhibition, but I don't think we are even close to being able to make a definitive statement on the overall quality of light reaching a given coral.

That specifically relates to the OPs topic. What we perceive as white can be made up of very different spectra. There is an online vendor that provides an "ocean coral white" LED made up of Cyan, red and blue, so a very incomplete spectrum, yet it looks white to us.

So which "too much white" are we talking about? Is it 6500K white as one poster suggested? We know that lights with very different spectal output can have the same Kelvin rating. Now the question is about which 6500K light we are talking about? If it is 6500K white, why was (and still is?) the Iwasaki 6500K the best Halide for growing corals?

For those corals that were negatively affected by too much light in a given aquarium, were there other deficiencies, like missing nutrients, fluctuating or incorrect alkalinity, poor flow...?

We know that corals do not get 100% of their nutrition from sunlight. What is the relationship between nutritional health and light?

I also recall you writing about different clades of zooxanthellae having different absorption spectra and that a given coral may recruit different clades at settlement. How does this affect what is the 'best spectrum of light" for that coral?

Lastly, I want to turn to human nutrition and health as an analogy why we should be cautious about the specific makeup of light and coral health. In an interview, a food scientist, one of the people who does primary research on human nutrition had this to say about the 'best' diet: "Eat unprocessed food, mostly vegetables, and lots of raw foods." Why was his recommendation so generalized? Because, after decades of research and billions spent, we still know very little about human nutrition and health.

Think about how much less we know about overall coral nutrition and health let alone the specific topic of the quality of light.

My own personal feeling is that we spend too much time "in the weeds" on the details of lighting and not enough time on the overall conditions in the tanks we keep our corals in.

P.S. My apologies if this turned into a bit of a rant. I strongly believe this is a much more complex topic than we think it is.

The more I learn, I realize how little I know.

 

[fredk]

Here's a chart showing spectra transmission in the 'clearest' seawater (Jerlov Type I Oceanic) at 1 and 10 meters.

...

The more I learn, I realize how little I know.

Thanks for the chart Dana. It confirms what I [think] I remembered.

It doen't help that the little I know is slowly fading from memory as I age.

 

[Dana Riddle]

And for a slightly 'dirtier' Oceanic-type water.