My PAR levels at peak intensity

[MnFish1]

I don't think I've posted this info before = photosaturation points for various corals. Bear in mind that the light intensity required for saturation decreases as depth increases - this accounts for some of low values seen in some of the Acropora species. The high value seen (Porites lutea) was from a purple shallow-water specimen. The only super high value seen was in Tridacna clams - give these guys as much light as you can.

Right - My interpretation was that after reaching photo saturation - the curve was relatively flat - and then at much higher PAR values damage occurred. But - that there was still a great variety of tolerance between the photo saturation point and where it seemed like light was 'detrimental' to the coral. Ie. if the photo saturation point was 150 - damage didnt start occurring at 160? Can you comment on flow and alkalinity vis a vis this topic?

 

[cain720]

What differences have you noticed at these lighting levels vs. normal levels under 600 par or so?

 

[Dana Riddle]

Any idea about tenuis?

Not sure about A. tenuis. I generated some of that data, other was from various research papers.

 

[Dana Riddle]

Right - My interpretation was that after reaching photo saturation - the curve was relatively flat - and then at much higher PAR values damage occurred. But - that there was still a great variety of tolerance between the photo saturation point and where it seemed like light was 'detrimental' to the coral. Ie. if the photo saturation point was 150 - damage didnt start occurring at 160? Can you comment on flow and alkalinity vis a vis this topic?

These are the basic stages in zooxanthellae photosynthesis:
Compensation Point: When oxygen production meets the respiration requirements of the zoox.
Saturation Point: When increasing light intensity no longer increases rate of photosynthesis.
Dynamic Photoinhibition: Natural defenses (the Xanthophyll Cycle) protects zoox/host from oxygen radicals/hydrogen peroxide generated by zoox/host.
Chronic Photoinhibition: Xanthophyll Cycle no longer able to defend against oxygen radicals/H2O2 and damage occurs. If damage exceeds ability to repair, then death could occur. Bleaching also probable.
Re: Water motion/alkalinity. Insufficient water motion creates an area of stagnant water (the millimeter thick 'boundary layer') around the coral and gradients can exist. 'Good' water decreases the boundary layer and allows migration of nutrients/micronutrients into the coral. Alkalinity acts as the carbon source for photosynthesis (eventually incorporated into simple sugar) and as a carbonate source for skeletal growth. Water motion and alkalinity can increase rate of photosynthesis independently, but can also act in synergy.

 

[Dana Riddle]

Here's from my zooxanthellae database. Didn't paste very well. First column is zoox clade (C,C1,C2, C3, D2, C3i): Clade C is an early attempt to ID - refined capability found various C Clades. C1 and C3 are 'weedy' clades and highly adaptable. D2 is a opportunistic clade when coral is exposed to high temperatures. Second column - coral species. Third column is location and 4th is depth (in meters) if known.
C Acropora tenuis Feather Reef, C. GBR 10-17m
C1 Acropora tenuis Curaçao Is., C. GBR 1-6m
C1 Acropora tenuis Magnetic Island, GBR ?
C1, C2 Acropora tenuis Magnetic Island, GBR ?
C1, D2 Acropora tenuis Feather Reef, C. GBR 10-17m
C2 Acropora tenuis Central GBR
C3 Acropora tenuis Taiwan-KT 5.0-8.0
C3 Acropora tenuis Rib Reef, C. GBR 10-17m
C3 Acropora tenuis Okinawa, Japan 1-10m
C3 Acropora tenuis Heron I., S. GBR 3
C3i Acropora tenuis Heron I., S. GBR 10

 

[Reefltx]

Yeah those are some crazy numbers. I have a green cap that’s yellow and it’s getting high par at 400. But yours is solid green at 750!!

It’s possible nutrients played a part, as yours is considerably higher than mines.

 

[MnFish1]

These are the basic stages in zooxanthellae photosynthesis:
Compensation Point: When oxygen production meets the respiration requirements of the zoox.
Saturation Point: When increasing light intensity no longer increases rate of photosynthesis.
Dynamic Photoinhibition: Natural defenses (the Xanthophyll Cycle) protects zoox/host from oxygen radicals/hydrogen peroxide generated by zoox/host.
Chronic Photoinhibition: Xanthophyll Cycle no longer able to defend against oxygen radicals/H2O2 and damage occurs. If damage exceeds ability to repair, then death could occur. Bleaching also probable.
Re: Water motion/alkalinity. Insufficient water motion creates an area of stagnant water (the millimeter thick 'boundary layer') around the coral and gradients can exist. 'Good' water decreases the boundary layer and allows migration of nutrients/micronutrients into the coral. Alkalinity acts as the carbon source for photosynthesis (eventually incorporated into simple sugar) and as a carbonate source for skeletal growth. Water motion and alkalinity can increase rate of photosynthesis independently, but can also act in synergy.

Do you have an estimate between. the saturation point and the chronic photo inhibition point for various Corals (I.e. do the PAR levels posted here by the OP make 'sense'.). My GSP is at a PAR level of 700 - (via a PAR meter - Neptune) - so I think my corals might be getting 'too much' light - but none seem to be suffering

 

[Dana Riddle]

Do you have an estimate between. the saturation point and the chronic photo inhibition point for various Corals (I.e. do the PAR levels posted here by the OP make 'sense'.). My GSP is at a PAR level of 700 - (via a PAR meter - Neptune) - so I think my corals might be getting 'too much' light - but none seem to be suffering

The difference between photosaturation and chronic photoinhibition depends on so many factors. Adaptive capabilities to high light is important. Fluorescent proteins, if present, can absorb UV/violet/blue light (mostly) and can shunt light energy away from the photosystems. Non-fluorescent proteins, if present, can reflect important photosynthetic wavelengths. Low water motion can inhibit photosynthesis due to poor diffusion of necessary nutrients through a thick boundary layer. And so on. But here goes (PAR values):
Coral Saturation Photoinhibition Difference
Pavona varians 110 350 240
Montipora capitata 135 250 115 This coral adapts very poorly to high light.
Porites lobata 250 350 100
Porites lutea 400 750 350 Strong purple chromoprotein present
Tridacna maxima 600 None seen at 1,900 n/a

 

[MnFish1]

The difference between photosaturation and chronic photoinhibition depends on so many factors. Adaptive capabilities to high light is important. Fluorescent proteins, if present, can absorb UV/violet/blue light (mostly) and can shunt light energy away from the photosystems. Non-fluorescent proteins, if present, can reflect important photosynthetic wavelengths. Low water motion can inhibit photosynthesis due to poor diffusion of necessary nutrients through a thick boundary layer. And so on. But here goes (PAR values):
Coral Saturation Photoinhibition Difference
Pavona varians 110 350 240
Montipora capitata 135 250 115 This coral adapts very poorly to high light.
Porites lobata 250 350 100
Porites lutea 400 750 350 Strong purple chromoprotein present
Tridacna maxima 600 None seen at 1,900 n/a

Thanks as usual

 

[spsick]

Those are some crazy numbers, and I’m not surprised to see you have high nitrates and Alk that allow you to run that much light. Am I to guess you don’t run a refugium and limited filtration as the corals are taking up nutrients so aggressively.

You have some amazing colors, which is the goal right? As long as they are growing why is everyone freaking about photo-inhibition/saturation?

Different things work for different people. Nothing is easily duplicated.

Beautiful tank!!

 

[Dana Riddle]

Those are some crazy numbers, and I’m not surprised to see you have high nitrates and Alk that allow you to run that much light. Am I to guess you don’t run a refugium and limited filtration as the corals are taking up nutrients so aggressively.

You have some amazing colors, which is the goal right? As long as they are growing why is everyone freaking about photo-inhibition/saturation?

Different things work for different people. Nothing is easily duplicated.

Beautiful tank!!

When I managed a commercial coral farm back in the 90's, almost all of the really colorful corals grew so slowly that they weren't a viable product. Back then, the general opinion was that more light was better and were blasting them with PPFD values approaching 1,000. Of course, we now understand that more light is not always best, especially in a commercial, profit-driven situation.

 

[MnFish1]

When I managed a commercial coral farm back in the 90's, almost all of the really colorful corals grew so slowly that they weren't a viable product. Back then, the general opinion was that more light was better and were blasting them with PPFD values approaching 1,000. Of course, we now understand that more light is not always best, especially in a commercial, profit-driven situation.

What is your opinion in a normal 'human's tank' situation?

 

[spsick]

When I managed a commercial coral farm back in the 90's, almost all of the really colorful corals grew so slowly that they weren't a viable product. Back then, the general opinion was that more light was better and were blasting them with PPFD values approaching 1,000. Of course, we now understand that more light is not always best, especially in a commercial, profit-driven situation.

That totally makes sense. I remember tons of 400w and even the occasional 1,000w halide bulb with VHO to boot! Absolutely in a farm op you want to right amount of light to maximize photosynthesis and therefore coral output, and minimize electricity consumption.

I just hoped to put it in perspective and steer the conversation back to appreciating the OP’s tank rather than question numbers or viability. Although surely they knew posting #s like that would stir the pot

Can it be done? Sure- proof is in the pudding. I have a smaller system and also value color over growth.
Should it be done? Probably not unless it works for you.

 

[tnyr5]

It was mostly just: "here are the numbers" with a sprinkling of: "I wonder if this will stir the visceral, almost religious reaction that I think it will?"

 

[justingraham]

It was mostly just: "here are the numbers" with a sprinkling of: "I wonder if this will stir the visceral, almost religious reaction that I think it will?"

So u said u have had only had it this way for three months if I remember correctly?

If that is correct has consumption changed? How about color in the corals?

I believe anything is doable I just think it red lining your tank and if god forbid something happens

 

[tnyr5]

You'll all have to forgive me for being absent after this, I'm having a bad tmj flare up today and I'm in pain, so I don't want to take it out on my reef2reef bretheren.
This tank has been running for 1 year and 5 months and most of the corals you see are less than a year old. The old lighting was two radions running on the same schedule, so these corals were already getting a ton of light. I upgraded the lighting about 5 weeks ago. Two- part consumption nearly doubled over the course of a week, and it took a little time to get everything adjusted. During that two-week adjustment, growth stalled. Once things were on track, colors on the (supposed) gemmiferas got significantly more intense and the fast growers have resumed their typical 1/2in per month. Most grow slower than that because they are notoriously slow-growing corals to begin with, and were chosen for this small tank for that reason.
I make no claims that my way is better or worse than any other.

 

[JSpen]

How do you acclimate new coral to such high par? WhTs your routine?

 

[Bpb]

Information on this topic is so frustratingly conflicting. Conventional wisdom for the last 20+ years is the more par the better, the closer to 6500k the better. Now only recently are vendors and hobbyists alike adopting the 20k to just plain solid blue at 100-200 par for maximum growth philosophy. And the two camps will never seem to agree. I can say with absolute certainty, that sps in my tank seem to grow the fastest in the 250-350 range, less than that and colors get real drab and growth slows to a crawl, more and colors tend to get very vibrant with more rainbow present, but growth tends to really start to get sluggish (in the 500-700 range)

 

[tnyr5]

How do you acclimate new coral to such high par? WhTs your routine?

I throw them in and let them deal with it lol.