PAR rant

[saltyfilmfolks]

Well, maybe it's mincing words, but I said they are a response to stress. (Which is what I was attempting to explain, in a nutshell.) There should be no question that they are under stress.

Here's another angle:

Being photosynthetic is not a cnidarian's natural state. (As a family, they are deep-sea creatures.) It's an adaptation to a dinoflagellate infection that they have become expert at managing – expert enough to use the infection for food and energy (and more).

But, as I briefly described, the direct and indirect side-effects of being photosynthetic result in cellular damage. Cellular damage is stress.

Since corals can "get their fair share" from very little light (thanks especially to the photosynthetic pigments and their antennae pigments) and too much light actually damages them, they have these light-handling strategies that they use these to minimize cellular exposure to these direct and indirect effects.

This is the light acclimation we casually refer to....and what happens when we move corals that have had time to grow and adapt. They no longer have their photo-receptors and shields in the right places and start suffering damage and other related problems when light starts hitting their "soft parts".

What's brilliant about it though, is the same system also maximizes the useful light they are exposed to so they can operate in minimal light situations too.​

I don't know if you already looked at the "In situ..." article linked above, but I suspect you'd like a lot of what's in there. It's one of the most current articles on the subject I've bumped into. (And overall one of the most amazing articles I've bumped into. If you didn't already think corals were amazing, this article should do it.)

Going just from memory I think this one has some good tidbits on that front, though more on the stress angle than the pigmentation angle:
Is the coral-algae symbiosis really ‘mutually beneficial’ for the partners?

I hope this helps!

I find it the most interesting observation from the old guys that, they'd get acros strait off the boat in the old days and just blast the heck outta them with an array of MH's and they LOVED IT!
Id surmise you need stressors to stimulate growth and color.

If you think about it flow is also a stressor.

 

[saltyfilmfolks]

I think you nailed it on the head – this is one of their forte's.

Light at-depth for them is very blue-blue-green and not much other color to speak of and they seem to make it work!

On a tangent: Did you ever realize that chlorophyl emit their own red light? At-depth it's all the red light there is, and it combines with other far-red "waste light" in the "Emerson effect" which is a boost in photosynthesis using nothing but "waste light".

Amazing.

lol.
get deeep.
The color Red is only a few Nm short of....heat.

 

[mcarroll]

Ya, they are fueling photosynthesis with 670nm "waste light" and 700nm "heat". Way cool.

 

[scoopsthedog]

You are correct sir.
how rare

so is @Dingo



correct. and a par meter can be fooled. quite easily. like many things its up to us to know how to use the tool.
I spoke to a member here recently with coral probs and he said he had 250 par. but the light was 30% white and 75% blue.
well yes the corals probably dont like 35,000k.


yes. is quickly absorbed.
but a meter will register high par on a single spectrum of high intensity.
and although some red is visually lacking its a longer wavelength than the others and does actually penetrate resulting in the bit of red we see in "optimal reef light charts". and likely what spurs so many debates amongst science as to its use by the coral.


book is being rewritten now that fish also glow.
IMO monkeys have bad eyes. its always bright where they live. A mantis shrimp would probably know.


its sunscreen according to Dana. and also camouflage and likeley feeding tools. and can be considered a stress event as its more prominent when Photosynthesis shuts down.
why they have color period is a good question. we know why berries are red and flowers have color. I would assume corals have color for the same reasons.

thats said, the same coral can and does grow in the shallows and and depths.

So PUR. and how a corl figures out what it wants.
A coral at the surface is getting an even spectrum of 5600k. 15ft down its 10,000k. 20ft 20k. also each depth is a lower and lower Par.
Does it look a bit different, probably. esp if it gets pars higher than the 350 dana suggests. OR is only getting wavelengths that stimulate specific carotenoids and producing only specific tints as a result of "uneven tanning"
if were on a north facing slope w less direct sun its color temperature would actually be cooler. but it still grows. would it look the same ? not sure, but probably.

but here's this.
Take some coral and put it under a 48,oook Phillips led from home depot. Check that the spectrum is fairly even( like daylight), with a spectrometer. (a par lux test would be fun too)
put it on the corals and see what happens.
Hint. It grows corals perfectly.
none of the corals after a year or more looked any different then ones I had seen before. Visually some appeared "dull" as there's no 420 somthing to make them "Pop" like under reef lighting.(remember they're engineered for aesthetics too). but were otherwise completely normal. especially once put under standard reef lights.

So. Id say the coral will take whats available and use it.
Its likely major overdose and under dose of specific frequency is where you get into trouble.

Part of the issue (I assume) is that with a mixed reef system you have Coral that grow in shallow environments and some that thrive in deeper ones. What is the best way to find a mix of intensity and spectrum of W /B using LEDS? Can coral adjust to greater intensity over time?

 

[mcarroll]

I find it the most interesting observation from the old guys that, they'd get acros strait off the boat in the old days and just blast the heck outta them with an array of MH's and they LOVED IT!

I don't remember folks getting consistent results with anything back in the day (what's alkalinity??).....but I'm not sure how far back you're thinking.

I've got a nice two tank-one system setup with around 50,000 lux (>700 PAR) on one tank and 15,000 lux (<375 PAR) on the other – measured at the water surface. I see almost no aesthetic difference between identical corals grown in both tanks.

If I had time and funds it would be fun to test a wider range of corals than just what I keep and maybe another level of intensity, but on the reading and evidence so far I still say that a healthy tank is, for the most part, all it takes.

 

[mcarroll]

Part of the issue (I assume) is that with a mixed reef system you have Coral that grow in shallow environments and some that thrive in deeper ones. What is the best way to find a mix of intensity and spectrum of W /B using LEDS? Can coral adjust to greater intensity over time?

Generally speaking, they can adjust to brighter and less-bright environments.

But experiments have shown that changes like this can also lead to mortality.

The animal is capable, but it depends on circumstances like anything else. Which dinoflagellate clade(s) do they have? What's the water flow, light and nutrient conditions in their location? Of course the magnitude and frequency of changes/disturbances like this count too.

The best mix/spectrum is probably 2:1, 1:2 or 1:1 depending on your tastes. Corals aren't going to care too much between them.

 

[reefwiser]

I find it the most interesting observation from the old guys that, they'd get acros strait off the boat in the old days and just blast the heck outta them with an array of MH's and they LOVED IT!
Id surmise you need stressors to stimulate growth and color.

If you think about it flow is also a stressor.

This was because we where using full spectrum light sources. [emoji3] MH. Today's hobbyist are fascinated with trying to get corals "POP" with color using pin light LED fixtures. That laser light on to the corals surface. This laser effect is why people use LUX and Par to keep from killing corals with these types of lighting. Problem is that until recently Par meter have not been able to read the Par coming out of LED's

The human is completely useless to judge the spectrum of light the corals need. No two humans can even see colors the same so how can "WE" judge the spectrum that the corals need.

The "old guys" just knew it was best to give the corals as close to a full spectrum of light that we can.

 

[griff500]

I don't wish to appear rude (I know how sensitive people are these days to words), but I'm not quite sure what the point of the thread was. Nobody is going to light their corals with red light only. PAR is a very good way to measure intensity and spectrum is a different topic which has been discussed extensively. If you look at the CoralLab AB+ spectrum it's high blue and lower everything else - surprise surprise. Measuring PAR is a great way to ensure that the corals don't get more intensity than they need and to figure out placement of various corals based on variations in PAR through the tank.

I would put water quality and flow well above lighting, assuming that the spectrum and PAR are not in a weird place.

 

[Surfandturf]

I don't wish to appear rude (I know how sensitive people are these days to words), but I'm not quite sure what the point of the thread was. Nobody is going to light their corals with red light only. PAR is a very good way to measure intensity and spectrum is a different topic which has been discussed extensively. If you look at the CoralLab AB+ spectrum it's high blue and lower everything else - surprise surprise. Measuring PAR is a great way to ensure that the corals don't get more intensity than they need and to figure out placement of various corals based on variations in PAR through the tank.

I would put water quality and flow well above lighting, assuming that the spectrum and PAR are not in a weird place.

I think that one of the things you are missing from this post is that coral placement matters. If you have a coral that is a deeper water coral and is naturally used to less lighting, then putting it under more intense lighting will be more damaging. There was a video that was posted on this thread that I found to be very informative. There is a point where a particular coral will receive all of the "light" that it needs, anything additional to that, and it just becomes counterproductive. I think that is a very important lesson to be learned in this hobby.

 

[griff500]

I clearly mentioned placement in my post - last sentence in the first paragraph.

 

[saltyfilmfolks]

This was because we where using full spectrum light sources.

MH. Today's hobbyist are fascinated with trying to get corals "POP" with color using pin light LED fixtures.

yup..

The "old guys" just knew it was best to give the corals as close to a full spectrum of light that we can.

And there is that.
And the debate still rages as to HOW MUCH light. MH is beautiful light, and a LOT was used too.
And now led companies are struggling to go back to that. In spectrum for some and intensity for others.

 

[saltyfilmfolks]

I would put water quality and flow well above lighting, assuming that the spectrum and PAR are not in a weird place.

I would keep them exactly equal. light is an equal parameter.
good points btw.

Measuring PAR is a great way to ensure that the corals don't get more intensity than they need and to figure out placement of various corals based on variations in PAR through the tank.

If you have a coral that is a deeper water coral and is naturally used to less lighting, then putting it under more intense lighting will be more damaging.

This something I really want to know more about. My xenia acro gorgs palys zoas etc are all getting the same amount of light and have been for months. so is there som myth involved? or science.
But yes, you need to measure and know how much light you have like any other parameter. Par however is has a number of unintended variables.

If you look at the CoralLab AB+ spectrum it's high blue and lower everything else -

Id would assume a 16k. yes? probably less.

 

[saltyfilmfolks]

Part of the issue (I assume) is that with a mixed reef system you have Coral that grow in shallow environments and some that thrive in deeper ones. What is the best way to find a mix of intensity and spectrum of W /B using LEDS? Can coral adjust to greater intensity over time?

so far yes, highly adaptable. and watch the coral for cues.
I go by eye, what color looks good on my tank. its probably going to land between 10k and 20k. past 20k stuff looks funny or too blue.

Id say most may forget, some led blue(in many fixtures) are not really a kelvin color color just the narrow bands at the high end to be balanced with the "whites". stuff would probably grow but bleh.
white btw is not white but 8 to 14,ooo kelvin depending on the fixture.

 

[griff500]

I would keep them exactly equal. light is an equal parameter.
good points btw.

[...]

Id would assume a 16k. yes? probably less.

Possibly less but I'm not sure about that. It was apparently designed to get close to T5 if my memory serves me well and it's quite blue (100% on blues and 'UV', about 24% on whites and other colours, going from memory again).

I've seen quite wide variations of PAR levels and spectrum used on nice tanks and so I do think flow and water quality are of greater importance, but you certainly can't go wrong with treating them all as equally important.

Regarding your point about different corals getting the same amount of light and all doing well (I presume), I reckon that corals can adapt more readily to different light than to different (poor) water quality or a lack of suitable flow. That's another reason I place flow and water quality ahead of light but I'm obviously not saying that light (intensity and spectrum) isn't important.

 

[scoopsthedog]

so far yes, highly adaptable. and watch the coral for cues.
I go by eye, what color looks good on my tank. its probably going to land between 10k and 20k. past 20k stuff looks funny or too blue.

Id say most may forget, some led blue(in many fixtures) are not really a kelvin color color just the narrow bands at the high end to be balanced with the "whites". stuff would probably grow but bleh.
white btw is not white but 8 to 14,ooo kelvin depending on the fixture.

So would a 60%B / 30%W be an acceptable color range for most LPS and Zoas? I did notice my coral and nem are liking lower intensity for a 8 hour on cycle.

 

[saltyfilmfolks]

Regarding your point about different corals getting the same amount of light and all doing well (I presume), I reckon that corals can adapt more readily to different light than to different (poor) water quality or a lack of suitable flow. That's another reason I place flow and water quality ahead of light but I'm obviously not saying that light (intensity and spectrum) isn't important.

dunno, i havent experimented or likely made enough mistakes yet to learn from.. Ive had montis continue to grow with stupid low calcium and high Po. zoas shrink from not enough nutrints and also brown from to much. many softies "love dirty water" and thrive. that would be considerd "poor quality" i believe.

So would a 60%B / 30%W be an acceptable color range for most LPS and Zoas? I did notice my coral and nem are liking lower intensity for a 8 hour on cycle.

depends on the fixture what that balance is, but IMO does the tank look great when you look at it? Part of my point is "they" don't seem to care as much about color assuming a half decent fixture.
See diesel's post above. about going to les and less blue. It still HAS blue.

On could I suppose therorize that the more blu thing was from back in the MH days when an Iwasaki 14k was replaced w a 20k radium and "the corals liked it", not because it was more blue but because the Iwasaki(or insert any brand) didn't actually have enough period to really be 14k.
What??? a manufacturer "stretched" the truth?

this is actually how myths are born. Take ginger as another example.

 

[griff500]

dunno, i havent experimented or likely made enough mistakes yet to learn from.. Ive had montis continue to grow with stupid low calcium and high Po. zoas shrink from not enough nutrints and also brown from to much. many softies "love dirty water" and thrive. that would be considerd "poor quality" i believe.

When I transferred to the current tank I had the old one full of crap, no heater, no rocks, no equipment of any sort, no feeding, no fish and no lights for a few weeks - just a still tank of old water and sand - and it had a 'dead' sun coral left in it - the only thing that I didn't transfer. When I finally got around to emptying and removing the old tank I found the sun coral looking like new. Obviously it's non-photosynthetic, but even so, it had no heat and no food going into the tank... go figure. I think SPS are going to be far less tolerant of poor flow or water quality than some other types of coral but can adapt to different lights. Anyhoo, we are all making (educated) guesses and constantly learning what will work for our individual tanks.

 

[saltyfilmfolks]

I think SPS are going to be far less tolerant of poor flow or water quality than some other types of coral but can adapt to different lights.

Ive been trying to kill my acros for some time.(sarcasm) its def interesting. what I though would have and should have been bad was beneficial sometimes.

Anyhoo, we are all making (educated) guesses and constantly learning what will work for our individual tanks.

exactly.

 

[Surfandturf]

So while on the subject of light, how long do you leave your lights on per day? Do you leave it as a constant or does your light gradually decrease through the day? I leave mine on for 12 hours and thinking of cutting it to 10 after reading these posts.

 

[saltyfilmfolks]

me im led. peak for 8 hrs.
lights on at 6am off at 10 pm