Will do, thanks. 
Back on topic, I’ve had about six months with an HLG 135 Rspec now. I have no led experience to compare to, but I have been pretty impressed with the results for a small cabinet. The light was very pleasant to work around, and a dream come true for seeing the plants properly while working; night and day difference than trying to see what’s up under an hps. I turned it down to 100 watts in veg, and it kept the nodes nice and close. Turned it up to 150 for flower and things finished nicely. I have no other input on the spectrum as far as plant growth is concerned, but really did enjoy the color rendering and overall warmth while working under it.
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What color temp did you go with? I’ve found the 4000k diodes do best for me.
I went with the R spec, which is a mix of 272 3500k and 16 deep reds at 660 nm. Overall, the CCT is between 3150 and 3250, with a CRI of 90. Here’s the link to the HLG QB288 V2 R spec:
The R spec was pretty new when I got it, and I figured it looked like it was worth a shot. I may pick up a 4000k board at some point to compare for science. However my next light is most likely going to be one of the Elite 360 kits from HLG. I have a little 3x3 area six feet tall that I think would be perfect with the Elite 360.
I can say that even at 150 watts, it still ran cool enough to keep within a couple inches of the top of my cabinet with the driver on top of the aluminum heat sink. I didn’t have a fan directly on any of the light, so I was fairly impressed with the passive cooling. The mix of white and red leds made for interesting patterns on the floors and walls when the light would shine through the cracks between the cabinet and the doors when I would open it up, a fun added bonus in my mind.
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The patterns the put out through small holes is pretty neat haha, I noticed that too. But overall I’m not that happy with it. I have that same exact board with a couple other hlg boards in 4000k and the plants under it aren’t nearly as happy the others.
I have 3 boards in a 2x4x5 tent and try to keep them between 70-90w on each board, with the heatsink on em, they’re warm, but barely so.
I’ve had better results with the higher color boards like @ValueHorse. I’m almost tempted to get some 5700k strips and do a side by side in my two 2x2 tents to see the difference I see with lower to higher color temps.
Eb strips are crazy cheap right now so it’s cheap enough to get a few to play with.
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My guess is that the warmer white leds are lacking in the blue end of the spectrum. That would make more sense as to why it doesn’t work as well. I would still think the addition of far red leds could help, but I guess it could stunt growth too. Perhaps the lack of performance could also be attributed to having less white leds overall, since some are being replaced with reds. Either way, from your experience, the 4000k’s sound much better. I still want to play around with one of the Elite 360’s, but maybe not as much now. Been wanting to try out CMH too, but that’s a different discussion. I would love to do a diy strip build, but don’t really have the time and space to devote to tinkering now. Let us know if you do a run at 5700k!
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I did a test run with 4200k and 3000k spectrums in flower. This was done with cmh, but imo K is K.
The 4200k saved on power bills (not as hot as 3000k). Weight was down about 5-10%. Frost was on par. Stretch wasnt as much with 4200 vs 3000.
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I’m gonna do it haha, I’ll probably buy the strips today. They’re so cheap I right now, I can build a whole new light for under 100 bucks.
Take a look at the spectral power distributions of the leds. Energy per specific wavelength. Color temperature, K, is related to the over all perception of color dictated by the make up of its spectral distribution as it realted to a black body radiator. More effective at describing more conventional tungsten that use metal and heat to generate light.
Even geekier is IES TM 30 which breaks spectra down into a bunch of different metrics.
K is really too course of a metric for what you are examining, at the level of your percieved interest, but is great shorthand.
Most manufacturers have spds readily available.
SPDS are also good compare to action spectra of the various pigments.
Have any of you been playing around with altering of color (spectral composition) during daily cycle or otherwise? Something i have been curious to try but alas, am also lazy…
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The only thing I’ve looked into was adding far red at the end of a lighting cycle to mimic sunset.
I was actually thinking about this as I was going to bed last night haha.
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I will be doing the same thing with my quantum board fixture.
Emerson effect.
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I couldn’t remember the term for the life of me and was feeling too lazy to find it haha.
I’m curious to see what it adds to things. I just pieced together a little 10w light for it, and the next batch I flip into flower I’m going to use it.
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The all on, all off approach is certainly unnatural and I wonder if there is consequence due to lack subtle ramp up and down?
I know if I start and end my day like that…I wouldnt be feeling too well and my performance might suffer…there I go anthropomorphizing plants again…
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to my knowledge, this is what emulating the Emmerson effect with far red 15 minutes before lights on and 15 after helps address. I’ve also seen digital dimmers that could potentially be hooked up to a phone App. in which case I imagine you can program a dim schedule.
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So which bulb did you like better overall, 3000k or 4200k?
3k (930 Philip’s bulb) flower for flower had better results. I only run 3k in flower now. I keep the 4200k (942 philips bulb) for the veg room. I use t8 led t8 tubes in clone and on the sides of my veg room.
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did you ever run a 3500, or is that temp not as common for CMH?
I’ve only heard of 3k amd 4200k. Other bulb companies may have other options.
The Emerson Effect is something different, but far red related. Basically plants given far red on top of shorter nm spectra perform better than the sum of their parts in what I would call almost an in vitro study. Kind of like measuring absorptance of plant pigments by isolating each pigment in a specimen individually, running them all through an optical spectrograph, and then adding the results. You’re likely to get something that differs wildly from the actual in vivo absorptance of all the pigments in concert. That’s another thing to keep in mind: the higher your radiant density, the more the McCree curve flattens out, optimizing spectra for photosynthesis stops making sense when you’re hammering plants with 1100 ppfd.
Generally, the efficiency of phospor white LEDs made narrow wavelength horticultural LEDs obsolete. If you’re using white light, not even LEDs particularly, you’re most likely getting some far red with the rest of the visible spectrum and it’s enough to leave it at that without adding high-wattage 680nm sources. I have not seen any difference in using “flower initiation” far-red before lights out (there is already far red in the white spectrum, doesn’t make sense to supplement what it’s already getting).
I also ran one of those arduino Storm controllers for aquariums back in the day and did the sunrise-sunset thing, very lame, don’t do it. What I will say though, that storm controller had a “passing clouds” function that would randomize dimming at a programmable frequency, I could see some potential with kwh savings utilizing that as almost a low intensity strobe. Thing was clunky though, 10v inputs and Meanwell drivers pwm control leg is 5v so you have to build a little step-up board to get them talking There’s probably better ones out there now if anyone wants to tinker with that sort of thing. The clouds thing also had the odd effect of being extremely relaxing. I would read for hours at a time in my rooms over the winters, it dead nuts feels like you’re outside on a nice day.
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HLG has a new quantum board, the QB 648 Diablo:
https://horticulturelightinggroup.com/collections/quantum-boards/products/qb648-diablo
Looks pretty beasty with a copper board for better heat sinking and over twice the LED’s of their normal qb’s. It was designed by HLG and produced by Samsung. Looks like it’s an R-Spec type spectrum with enhanced red spectrum, and looking at their graphs, it looks like it’s making more in the blue spectrum too. It looks way better than the graph for the 288 R-Spec.
They also have the QB 288 available in B-Spec with enhanced blue spectrum.
I like how they are advancing their products so quickly. Gives us lots of options to dial in our specific grows. Of course they came out with both of these new designs right after I blew my lighting budget. 
What brand are the gen 1 and gen 2 that you mentioned please