Are "Low Light Corals" A Myth?

[saltyfilmfolks]

I have a friend who runs several 250w mh radiums in his tank old school style with a fairly long duration.

At the top of the water it's over 100,000 lux.
The closest coral is less than 12in below the water.
And yes. It's an amazingly beautiful tank with great growth and color.
I've seen a lot of tanks done this way as well.

It's kinda what drives me, not only solving the problem, but understanding the success.

 

[Dana Riddle]

I have a friend who runs several 250w mh radiums in his tank old school style with a fairly long duration.

At the top of the water it's over 100,000 lux.
The closest coral is less than 12in below the water.
And yes. It's an amazingly beautiful tank with great growth and color.
I've seen a lot of tanks done this way as well.

It's kinda what drives me, not only solving the problem, but understanding the success.

This could well be a situation where xanthophylls shunt the Radiums' blue light away from photosynthesis, thus allowing the coral to fare relatively well in a high light environment. Walz offers a new PAM fluorometer that allows the user to investigate the effects of variously colored LEDs (these are built-in.) I can do the same thing with mine - I just turn the meter's actinic light off, use the Li-Cor PAR meter to measure light intensity and then plug the numbers into a proprietary Excel spreadsheet to calculate rates of photosynthesis (relative electron transport rate, or rETR.) Fun stuff!

 

[HolisticBear]

It's kinda what drives me, not only solving the problem, but understanding the success.

But if that same reefer had run another tank that was only 200 PAR for years, what would be the difference? Less growth, fewer yellows?

Hobbyists typically want more, not less, and more seems to beget more. More lights, allows or requires more flow. More light, allows or requires more nutrients.

Some accomplished people seem capable of growing almost anything, so their goal has moved on to something else. I think of zeovit not as a way of keeping/growing colors, but accomplishing a unique pastel look. If you can accomplish the same thing with 200watts, but you're using 1000watts, it feels wasteful. But maybe 1000watts is the only to get that weird color morph they crave?

Back to your original topic, has anyone grown an acan garden in 700 PAR? If no one has done it, that's one data point. And if someone has, how are they (health, color, growth, fragility)? Life has an amazing way to survive, so simply not dying doesn't seem like a high enough bar.

 

[saltyfilmfolks]

This could well be a situation where xanthophylls shunt the Radiums' blue light away from photosynthesis, thus allowing the coral to fare relatively well in a high light environment. W

Yes this was pretty much assumption.
Lower alk good nutrints and flow and the coral and a keen eye aside.
The adaptability of the coral to the light levels give him the results he enjoys.

It's def posssible there could be "improvement" but that really is in the eye of the beholder.

can do the same thing with mine - I just turn the meter's actinic light off, use the Li-Cor PAR meter to measure light intensity and then plug the numbers into a proprietary Excel spreadsheet to calculate rates of photosynthesis

Lol. You make it sound easy.

I'd rather sit in the blazing sun taking par measurements in Maui.

But if that same reefer had run another tank that was only 200 PAR for years, what would be the difference? Less growth, fewer yellows?

Hobbyists typically want more, not less, and more seems to beget more. More lights, allows or requires more flow. More light, allows or requires more nutrients.

Some accomplished people seem capable of growing almost anything, so their goal has moved on to something else. I think of zeovit not as a way of keeping/growing colors, but accomplishing a unique pastel look. If you can accomplish the same thing with 200watts, but you're using 1000watts, it feels wasteful. But maybe 1000watts is the only to get that weird color morph they crave?

Back to your original topic, has anyone grown an acan garden in 700 PAR? If no one has done it, that's one data point. And if someone has, how are they (health, color, growth, fragility)? Life has an amazing way to survive, so simply not dying doesn't seem like a high enough bar.

Overall I think its about method and comfort level.
You can have an amazing reef with little to no training and a horrible one with all the tools and a PHD

Perfection is a human fallacy. And more is a primative survival response that's been morphed into buying stuff to make things "better".

As far as your last question, yea, I'm pretty darn good at estimating par from lights and the spectrum of them. I've seen a lot of things on r2r and in person most reefers in general would say is not good or plain impossible as far as light levels. It's what helped prompt my original question. I've seen tanks tanks that are probaly 500 par on the sand because the light was what they could affford and the reef was thriving and beautiful. I also saw one that was under a Home Depot 48k led and was equeally thriving and beautiful.

Could they have been "better"? Depends on the definition.


I'm only on page 38 of a hundred of Danas article on light requirements and will have to read it again for the next couple years, but it's pretty much what I needed next time I see those tanks to understand how it's being done.

 

[HolisticBear]

The ability to tolerate high light has to do with their zoox's abilities to process photons, manufacture protective xanthophylls, mycosporine-like amino acids for UV protection, and so on.

Dana, you mentioned in the color pigment thread that some transitions are reversible, while another is a done deal once it reaches maturity. With regard to tolerating high light can these be done at any point in a coral's lifetime? Are corals more adaptable when younger? When @saltyfilmfolks talks of corals at very high light levels, is the possibility that they started from a 1" frag in that environment more likely that it would adapt vs something more mature?

 

[Dana Riddle]

Dana, you mentioned in the color pigment thread that some transitions are reversible, while another is a done deal once it reaches maturity. With regard to tolerating high light can these be done at any point in a coral's lifetime? Are corals more adaptable when younger? When @saltyfilmfolks talks of corals at very high light levels, is the possibility that they started from a 1" frag in that environment more likely that it would adapt vs something more mature?

Are we talking about light tolerance due to zooxanthellae type (clade)? Some researchers down in Oz found some Acropora specimens begin with one clade and switch to another as they mature. If you're talking fluorescence/photoprotection... I'd have to dig some of the references out to review.

 

[mcarroll]

But if that same reefer had run another tank that was only 200 PAR for years, what would be the difference? Less growth, fewer yellows?

Here's an anecdote that goes straight to your point.

My tank (to recap, it's 19" high) used to have dual 150-watt Radiums over it and I think that would register about 80,000 lux when the bulbs were new.

The tank got emergrncy-downgraded to about 15,000 lux worth of LED's (wish I'd bumped into Dana's lux meter articles sooner) and that eliminated ALL of the corals that were growing in about the top 8-10"of tank. (SPS were breaking the water across most of the surface of the tank.) But the rest of the coral that were growing lower survived and didn't seem to change color much.

Later on the LED's were replaced with about 50,000 lux worth.

To my eye, there's hardly a difference between the lighting regimes.
I don't doubt growth rates could be different, but I'd need to be very systematic to notice by how much.
I could point out some shape differences in the colonies between what is now the low-light tank and the medium-light tank.

That's about it.

 

[Dana Riddle]

Here's an anecdote that goes straight to your point.

My tank (to recap, it's 19" high) used to have dual 150-watt Radiums over it and I think that would register about 80,000 lux when the bulbs were new.

The tank got emergrncy-downgraded to about 15,000 lux worth of LED's (wish I'd bumped into Dana's lux meter articles sooner) and that eliminated ALL of the corals that were growing in about the top 8-10"of tank. (SPS were breaking the water across most of the surface of the tank.) But the rest of the coral that were growing lower survived and didn't seem to change color much.

Later on the LED's were replaced with about 50,000 lux worth.

To my eye, there's hardly a difference between the lighting regimes.
I don't doubt growth rates could be different, but I'd need to be very systematic to notice by how much.
I could point out some shape differences in the colonies between what is now the low-light tank and the medium-light tank.

That's about it.

Interesting comment on coral colony morphology under different lighting. I would think the colonies would tend to flatten out under lower lighting. Got a good laugh when I read your Roosevelt quote.

 

[mcarroll]

Interesting comment on coral colony morphology under different lighting. I would think the colonies would tend to flatten out under lower lighting. Got a good laugh when I read your Roosevelt quote.

Thanks for being here on R2R (long time fan), for commenting and for noticing the Roosevelt quote. (You're the first to comment about it. )

Differing shape could also be from a difference in flow between the tanks, but in the low-light tank the biggest morphology difference is on the classic Monti cap.....the plate is steeply angled like a funnel vs flat or only lightly angled like would be typical.

I assume this is to enhance prey/particle capture, but I haven't experimented.

Just guessing from some experience and info from this article:
Function of Funnel-Shaped Coral Growth in a High-Sedimentation Environment

 

[madweazl]

While poking around the internet, I stumbled across this chart from Seneye and noticed I don't really meet these minimums ratings for anything I have.

This monti receives 70-75 PAR at the peak of my 12 hour photo period (ramps from 11% to 40% over six hours and back down to 11% where the lights shut off) but it seems to retain its color and grow just fine.

Edit: Found an older image from Oct 2016 (just before switched to Kessil)

Today

How do you arrive at a minimum?

 

[Nano sapiens]

While poking around the internet, I stumbled across this chart from Seneye and noticed I don't really meet these minimums ratings for anything I have.
How do you arrive at a minimum?

Well, l think the Seneye ranges can be taken as 'in the ball park' since there are so many variables in regards to which coral does well at which PAR. Consider also that PAR from two similar output light sources can have quite different PUR...which then also effects how high a PAR reading is appropriate for a particular coral specimen.

For the Acropora granulosa, I know where that came from:

http://www.advancedaquarist.com/2007/3/aafeature1

53 PAR is the 'compensation' point and 107 PAR is the 'saturation' point. I suspect the other corals' data has been compiled from available online resources.

Ralph -

 

[mcarroll]

I stumbled across this chart from Seneye and noticed I don't really meet these minimums ratings for anything I have.

Your main problem with using that chart will be determining which species of coral you really have....molecular methods are needed, so you're mostly stuck with genus-level ID.

The second is that those are just numbers from a lab. True numbers they are, but they do not reveal any of the complexity of the situation that corals are in.

In reality corals don't really need light....just their dino's do.

Corals can literally survive in the dark as long as their food supply is sufficient in C, N and P. (The dino's are an ecological cheat so corals don't have to depend on their food supply for C most of the time.)

 

[madweazl]

Your main problem with using that chart will be determining which species of coral you really have....molecular methods are needed, so you're mostly stuck with genus-level ID.

The second is that those are just numbers from a lab. True numbers they are, but they do not reveal any of the complexity of the situation that corals are in.

In reality corals don't really need light....just their dino's do.

Corals can literally survive in the dark as long as their food supply is sufficient in C, N and P. (The dino's are an ecological cheat so corals don't have to depend on their food supply for C most of the time.)

Oh I had no desire to use it, just found it interesting that I literally had half the "minimum PAR" but still had decent results. I'm sure it would grow considerably faster in the ocean and maybe if I provided more light as well (not that I want it growing any faster since it's about the size I'll be keeping it at now).

 

[Subsea]

Agreed. another interesting thing i've found is people with higher nutrients get much farther with high intensity light than others. Well fed corals seem to tolerate / use high intensity lighting better than others.

Intense light requires sufficient nutrients to support growth. Your analogy with coral is interesting because I equate macro “going sexual” to be the extreme example of that. As a macro farmer, I have witnessed extremely heavy growth of macro growing under 1000W MH at 6500K in pristine clear water only to wake up in morning and not be able to see back glass on 150 aquarium. When macro that is growing extremely fast is deprived of nutrients, it dies and spreads spores of self survival or it “goes sexual”.