You guys may find this article quite fascinating.
Please note that the PAR numbers that are reported here wouldn't change much if they were all swapped out to "white LEDs only" because, according to the PAR meters, royal blue and white LEDs tend to put out VERY similar PAR numbers at the same drive current.
got any pictures to show?
Unfortunately not. I've checked the PAR of my array with several meters, just whenever my reefkeeper buds are over for a visit, and it's pretty consistent.
So I didn't really think to take data, sorry. I regret that I didn't.
My tank is only 9" deep though lol so it would be kinda hard to get much more data than "bottom" numbers
Very interesting. But hard to imagine how much PAR a single LED would put out. If I knew that and the spread it would be much easier to plan the light setup.
Are there any lenses? How is the spread?
My array sits about 23-24" from the substrate and uses 60 degree optics.
I don't have any data about PAR numbers and the light spread, but we will be having some PAR numbers coming up in about 1-2 months for A WHOLE LOT of LEDs and LED combinations--- along with spectral analysis. More news to come at 11.
For what it's worth, we hit over 14,000 micromols on a SINGLE royal blue Cree XRE at 960mA. Of course, that was with the Licor PAR meter sensor sitting almost directly on the LED's 60 degree lens. The Licor has a much higher "top end" than the Apogee meters, but it's also significantly more costly and not necessarily more accurate at sane PAR levels
Obviously that's only trivial data (kinda neat though
Also note that the PAR data from a single LED will be of value only to folks like Hoppy who have this supernatural gift of being able to calculate the total sum of PAR values for multiple light sources that overlap.
Meaning, the PAR of a single LED (with whatever optic) will only be useful if you know how to calculate how the other LEDs around it will increase the PAR values in any given spot.
Or if you're growing a 64-ounce picotope