I measure PAR 24/7
I have found that in my tank the recommendation of 250 to 350 ABSOLUTELY does not apply using my LEDs and my PMK which is based on an apogee.
My LEDs have to be run no higher than about 50% or they burn corals.
At those settings, my PMK only detects around 230 PAR during peak hours which is only 4 hours a day.
If i go any higher, the montis burn (killed one small frag), polys burn and die next followed by the zoas.
Oddly, the torches and hammers tolerate it...for a bit. The blue tort and an assortment of yellow, purple, green and red sps do fine up to just over 300 par for 4 hours a day, even up to 350-400 par (12k at 75%) but it seems to reduce growth when i over light them.
What really burns them is the 10k to 14k settings where the whites are up. Any thing above 40% and you are asking for trouble.
I only run that (12k) up in 8 minute increments about once an hour 6 or 7 times a day.
You can do 70% for 8 hours or so on 18k, 20k, all blue and my custom setting with all the blues at 100%, the whites at 19% and red and green 4 to 8% which is what runs the vast majority of the day.
Since heat is what degrades the LEDs, i suspect the power supply and main boards die LONG before the diodes. The cooling fans never come on and there is so much head room left that i suspect 10 to 15 years before id see 80% power levels required to hit 280par.
They are 2 years old and so far, not a single diode has failed.
Now the kessils are a different story. The older units run hot and are prone to fail at levels above 80% after a few years. The WE models run much much cooler but i suspect you might have a bit more drop in them. I could see hitting 100% power to maintain par at around the 7 or 8 year point. Still not bad considering you can get them for $325 if you know how to shop.
The setup is a 6ft long 225g running 3x hydra 52s and 4x Kessil A360ws.
Water is CRYSTAL clear as i run ozone, GAC and just installed a 30 inch, 50watt high output UV sterilizer.
Two days a week i don't even turn on hydras....kessils only. That keeps the color sharp and i find it gives the corals deep color.
Tank is only two years old and still maturing. Montis are growing fast as are the birds nest. Torts and other SPS have visible but steady slow growth and excellent color. New heads all over duncans and torches. Hammers stay about the same, zoas, polys and gsp grow almost out of control and acans and meat corals like scoli waste away and die.
