Metal Halide vs. LED Rates of Photosynthesis

[Mellotang]

If you are selling corals to Users of all
Lights then it might be detrimental to
Say one is better than the other

wouldn’t want to isolate any buyers

I feel certain lights are better for certain things but when it comes to high light living sps, halide can’t be beat

 

[Mellotang]

Debating is what advances the hobby!

 

[J1a]

How do you measure rate of photosynthesis?

if we are doing a study to measure rate of photosynthesis wouldn’t it make sense to
Use same spectrum and intensity

We can measure it through chlorophyll fluorescence. Like what @Dana Riddle said in the OP, he used a fluorometer.

 

[J1a]

IF you have the par and hang both high enough the geometry equals out..
Most rays striking the tank surface will be perp. or close to it..
Yes it is complicated..

I agree with you.

It is easier to compare apple to apple like this, and the measurement is actually achievable.

It would be really exciting to see how spectrum profile only affects the keeping of corals. Factually and without all the marketing talk.

 

[Mellotang]

I get a kick out of the debates and the passion behind many of the posts, everyone will have an opinion and at the end of the day we should try to remember that nothing we do is really natural when we keep corals in a box.

find what works best for you

take in whatever info you can get

enjoy The hobby!!

 

[Acros]

MH users generally tend to be seasoned reefers. Maybe that’s what makes for a healthy awesome reef tank and has nothing to do with MH lights.

 

[Mellotang]

I dont know

i feel like I could grow sps in a 5 gallon bucket with halide

if I tried that with LED they wouldn’t have the same resilience

 

[hart24601]

If you are selling corals to Users of all
Lights then it might be detrimental to
Say one is better than the other

wouldn’t want to isolate any buyers

I agree certain lights are better for certain things but when it comes to high light living sps, halide can’t be beat

Anyone that has known Adam as a hobbiest and then as a seller would strongly disagree. He speaks what he sees. He even had articles on the rampant abuse of photoshop in the hobby and with sellers. I know people that ran halides, switched to led and growth increased with their primarily acro display. MH is fine and if one likes it, use it, but it’s nothing magical.

 

[Mellotang]

Lol

maybe not magical but mythical!!

 

[hart24601]

MH users generally tend to be seasoned reefers. Maybe that’s what makes for a healthy awesome reef tank and has nothing to do with MH lights.

Spot on. Especially if they were “raised” when MH was the dominant form of lighting they have decades in the hobby by now.

 

[hart24601]

Lol

maybe not magical but mythical!!

haha. The myth part of mythical I strongly agree with!!!!

 

[oreo54]

Frontiers | Photosynthetic Acclimation of Symbiodinium in hospite Depends on Vertical Position in the Tissue of the Scleractinian Coral Montastrea curta

Coral photophysiology has been studied intensively from the colony scale down to the scale of single fluorescent pigment granules as light is one of the key ...

www.frontiersin.org

Coral photosynthesis is incredibly complicated..

 

[Mellotang]

Im my experience sps corals are more
Resilient when grown under halide

they can handle more fluctuation, can adapt to Different conditions better

when I grow under LED the corals let me Know immediately if something
Slips and they are hard to get back

the only saving grace i find with LED is I can lower intensity and try to
Recover

but again the things that affect my LED tanks don’t seem to be such and issue in Halide tanks

 

[Mellotang]

Maybe that’s why old School reefers were so generous and willing to trade
Things grew easy and quickly
Handled transitions from tank to tank easy

now you have these designer SPS that are so accustomed to ones specific LED light and conditions that they are difficult to transition to different tanks

 

[Mellotang]

Personally if it can’t be halide I prefer T5 to LED for Stability

 

[A. grandis]

Quite the opposite was seen in this specific experiment. Under Dana's study conditions, Pocillopora under LEDS did not undergo photoinhibition until the intensities were MUCH higher light intensity than the photoinhibition PAR under the halide. From eye-balling it, photoinhibition started at 300 PAR under halides but didn't occur until almost 500 PAR under LEDS. Moreover, at light intensities above 200 PAR, the Pocillopora under LEDS experienced MORE photosynthesis than under Halides. In other words, LEDS allowed more more photosynthesis at higher PARS and photoinhibition wasn't seen until intensities got even than those under halides.


Pocillopora

Exactly my point. And that must have something to do with spectrum!

 

[MichaelP]

Unless I am reading the data wrong this is a bit surprising. It seems like most most SPS tanks under LED are usually in the 300 PAR max range before burning the corals vs 500 PAR with MH. But according the chart it would be reversed?

 

[Mellotang]

 

[Mellotang]

Good ol iwasaki

before I could even measure par
Before GFO

ahhh

the good ol days

anyone got any iwasakis they want to sell!?

 

[Dana Riddle]

I don't want this is turn into a 'Ford vs. Chevy' debate. I present his info simply trying to better understand photobiology of corals under different lighting. I *think* what we're seeing is in the Poci (under LED lighting) is an example of non-photochemical quenching, which could include the photoprotective Xanthophyll Cycle (the conversion of xanthophylls and shunting blue light away from the photosynthetic apparatus). If this is the case, the same *might* happen under a metal halide generating mostly blue light. I do have the spectral data of at least the 400-watt Iwasaki 'daylight' 6500K MH I used (and used these with great success at the coral farm). I ran across this PowerPoint slide while looking for another for use in my upcoming MACNA Aquatic Expo presentation. I'll get back here as soon as I can.