DIY LED Lights Coloration Questions

[Roboson]

Hey Reef2Reef,

I'm building a DIY light fixture for my new 36g bowfront. I'm using par38 54 watt Bridgelux LED lights. Each bulb is actually an array of 18 3 watt LEDs. I'm thinking 4 will be more than enough, especially because I have no intention of keeping SPS corals in this tank. Right now I'm planning on it being a softy tank with maybe one LPS to see if it does ok.

What I'm really wondering is about the color. There are lots of options available and they are (theoretically) completely customizable by the manufacturer. One set that really caught my attention was 6 cool white, 6 royal blues, and 6 UV. Now I doubt that the UV are actually UV, but are instead just violet or even purple, but I was wondering if anyone had any input on how that light set up would look (not the set up itself, but the light within the tank) and what you would suggest for light color mix.

Short verson: Would 18 white, 18 blue, and 18 "UV" 3 watt par38 LEDs look good and provide the right spectrum for coral growth?

 

[Diesel]

!*!*!*! BUMP !*!*!*!

 

[Roboson]

Anyone?

 

[twilliard]

18 UV chips?
I would question the coloration.

 

[Roboson]

They're likely just violet, but they're made by bridgelux, so maybe they're legit. But it's my understanding that violet is useful for corals.

 

[twilliard]

They're likely just violet, but they're made by bridgelux, so maybe they're legit. But it's my understanding that violet is useful for corals.

It seems like a slight overkill with that many chips of UV
Also doing a 50 50 mix on your whites and blues may not be desirable. You would end up dimming the whites way back.
Also what drivers will you use? The number of chips per color may be too many for a single driver per color.

 

[Roboson]

I'm not super sure actually. I'm getting them in a bulb form which has the driver built in. I'm honestly doubtful it's as powerful as it says it is. But I figured for the cost it would still be pretty good. I'd get four 54 watt arrays for $75. Which would leave lots of room in my budget for supplementation or other things.

 

[ludnix]

Do you have much choice in the LED configuration on the Par38 bulbs? If so I would agree with twilliard, and do more blues, less whites and much less UV. They UV are probably actually UV with some violet, but they will most likely be lower spectrum UVA, which is not bad, but there are few LEDs out there that hit the higher UV frequencies without bleeding into the lower visible light spectrum as well. Since you can't individually dim each color with par38 bulbs your diode selection will pretty much set your coloration in stone. I would do more research, but I would probably do closer to 60%blue 40% white if possible and maybe a single UV per unit assuming you can pick the diodes on the bulbs.

 

[Roboson]

Do you have much choice in the LED configuration on the Par38 bulbs? If so I would agree with twilliard, and do more blues, less whites and much less UV. They UV are probably actually UV with some violet, but they will most likely be lower spectrum UVA, which is not bad, but there are few LEDs out there that hit the higher UV frequencies without bleeding into the lower visible light spectrum as well. Since you can't individually dim each color with par38 bulbs your diode selection will pretty much set your coloration in stone. I would do more research, but I would probably do closer to 60%blue 40% white if possible and maybe a single UV per unit assuming you can pick the diodes on the bulbs.

Turns out there's not much customization unless I buy in bulk. I could do one pair of the 6:6:6 bulbs and one of 10 blue 6 white. All the same wattage, but yes, none are individually dimable. There was one that had cyan in there. I think those are also 6:6:6, just with cyan instead of the UV. But from what I can tell, having a lot of cyan wouldn't be very useful to corals or be particularly pretty.

 

[ludnix]

I would personally only do one of the 6:6:6 and 2 of the 10:6. I don't think I've seen any fixtures made by hobbyists or professionals that use quite that much UV. Speaking from experience I know you can grow corals great with just 50/50 whites and blues, though you want to adjust the intensity for preference. My understanding is that UV is going to most beneficial to improved coloration of SPS which you're not planning on keeping. It might be worth having some in there for the visible light violet that they produce as a by-product, but wouldn't go too heavy with it. I think if I was building a LED for softies/LPS my ideal mix might replace some of the UV for a single red or cyan to improve the look of any LPS that have those colors like lobophyllia often do. I know you're constrained by the manufacturers though and I saw some of the bulbs on eBay that have some strange diode selections IMO.