Led Colors

[baseballfanatic2]

Hello, 

 

I am thinking about going 1 of 2 routes for my new 36 inch tank build with leds

all on different channels 

 

15 royal blue
8 cool white 
4 blue 
3 lime 

 

or....

 

all on different channels 

 

8 royal blue 

6 blue

6 cool white  

2 cyan 

3 lime 

3 amber 

3 red 

3 uv

3 violet 

 

Any recommendations? what would be your perfect led combo  on different channels? 

 

[DaJMasta]

It just depends on the spectral output you're looking for, both in terms of growth and looks, and the ease of driving them.

 

I assume this is for a custom (or customized) fixture, so there may be advantages to, for example, long strings for your chosen constant current driver if it's designed for higher voltage, which would probably mean fewer channels is better.  I always sort of liked the idea of lots of variety of LEDs, though it does usually come with some color abberation on the edges of shadows, but personally I wouldn't go with either - I'd much rather have warm whites over more discrete reds, greens, and ambers.

 

I find my personal taste tends towards whiter light - 10-15k equivalent in halides - so on my current XR15 G5 I've got the cool and warm whites up reasonably, but the greens and reds (I think two of each in their design), never get past 40%.  Now on a wider tank it gets harder to get good coverage using a small number of LEDs, so I could see wanting 3 spaced evenly edge to edge, but I still think my personal preference would be to have those turned down in operation, so more power available in them isn't really helpful.

The thinking behind the warm whites is that white LEDs have an intentionally much broader spectral output (that's why they appear white), so by having fewer discrete colors, you're still covering most of the spectral output.  While this has some relevance on coral growth and such, the big advantage here is color rendering and photography - if you have a lot of blues to make your colors pop, the amount of blue will overwhelm a camera's sensor (or just make it reduce exposure) unless you cut them with an orange filter (like an 85B or those ones sold as clip ons for phones), but when the filter cuts out the blue light for more reasonable exposure levels... if you haven't filled out other parts of the spectrum, the whole thing's just going to look dim.  If you go with whites, even in moderate amounts (maybe 1/3rd or 1/4 of the total output), you get enough light to get good color rendering, and the warm whites fill out more in the red/yellow area of the spectrum than the cool whites which fill out more in the green/blue part.


It's understandably complicated, but knowing that I want some output in the whole visible spectrum and that I prefer a whiter look than many do, I would arrange channels something like:
Violet/UV (and I'm not sure UV is really super necessary)

Royal blue/Blue

Cool White/Warm White

Red/Green/Amber if you want it (I probably wouldn't bother)

And then split channels where it's convenient for extra control.  The basic approach in my mind is that you want a blue channel and a white channel and that should be the majority of your output.  Violet/UV are a supplement for your blues, Red/Green are a supplement for your whites, but both are only there to help fill out the spectrum a bit, they really probably need only 10-20% of the output of either of the other channels, and with both kinds of whites, maybe not even that.

Also worth thinking about moonlights if you're DIYing, either a specific channel, or just tossing in a blue or two to your violet channel and using that as the moonlights.


**Edit: just looked up some spectral output graphs for warm and cool white LEDs, and it looks like the green channel, and to a lesser extent the red channel, is basically redundant.  I'd probably do Violet/UV, Blues, Whites, then Cyan and Red for those four channels to fill out the missing peaks in the spectrum.  This will depend on the outputs of your chosen LEDs, but it's probably similar among a lot of them, the technologies/materials used for different versions are not that specifically different in most cases.

[Reefkid88]

Swap the limes for mints. Ditch the cool whites for warm or neutral whites. The mint/limes will throw the color off. I've tried it and was not happy with the spectrum.