Well I'm shocked...Insane Amount

[BaliReefBox]

JUst thought I would check outside and see what the sun is actually putting out PAR wise. It is 1240pm and it's a brilliant clear day at longitude 8* south. The apogee 510 went to 3000PAR. So some of these zoas etc in shallow tidal pools are getting smashed with PAR.. makes the 200ish seem not very much at all.

 

[rtparty]

In the wild, most of them hit photoinhibition and then go into protection mode when PAR is that high

 

[Cichlid Dad]

Our tanks are a completely different environment then the ocean. I've seen video's explaining why 2000 par in the ocean is tolerable, but the same coral in our reef tank will bleach under 200 par. I don't remember all of the details, something to do with a closed system and water conditions if I remember correctly. That being said, I have zoa's in my reef growing at and near my acro with no issues.

 

[oreo54]

JUst thought I would check outside and see what the sun is actually putting out PAR wise. It is 1240pm and it's a brilliant clear day at longitude 8* south. The apogee 510 went to 3000PAR. So some of these zoas etc in shallow tidal pools are getting smashed with PAR.. makes the 200ish seem not very much at all.

Apogee 510 is " set" for under water.
If used "dry" you need to either use the conversion factor (1.25) or if possible switch to out of water.
So probably more like 2400 if corrected..
Still a lot- o- par. Just a picky point.
Ocean caustics can increase par by lensing but that is a different story.

A Different Look at Lighting: Effects of Prolonged Photoperiod, Spectral Quality, and Light Dosage

Some reef aquaria 'experts' have suggested that we understand all we need to know about lighting of reef aquaria. This article will suggest otherwise.

reefs.com

 

[Hooz]

If you look at a spectrum graph of that sunlight and then compare it to a Chlorophyl absorption chart, you'll see that the amount of that light that the coral actually use (PUR) is only a fraction of what the sun is providing. Modern LED lights are setup to hit the main points for Chlorophyl, and they can hit them hard. That's why it's easier to bleach coral with 200 PAR from an LED.

Back in the day when LEDs were new and people were switching from halides, it was hard to understand why coral that had been thriving under 700 PAR from halides crumbled under 200 PAR from (then, mostly 450nm) LEDs. A lot of that was because the "blue band" (the light the coral actually use) from the halides was a small fraction of the total PAR output, so 700 PAR didn't equal 700 PUR, but the full 200 PAR from the blue LEDs was PUR.

But, yes... That's still a lot of PAR, and probably a lot of PUR too, though.