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420nm LED pics over tanks?

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I am considering changing my 45g freshwater into a softy/LPS reef.


I already have a string of neutral whites, and a string of royal blues.


All I need now is a second "blue/actinic" string.


I'm either going to go with royal blue Crees (with a couple reds tossed in to purple up the tank some)---- or I'm going to go with mostly violet LEDs.




However, nobody local seems to have these so I can't see them with my own eyes.


Can anyone tell me how they look, when all the other LEDs are on??? Meaning, if I have 12 Neutrals, 12 Royals, and 12 of these 420s, will the 420's make any difference in the color that would justify the reduction in PAR output?





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Your eyes will have a hard time seeing the 420s (they are almost outside the spectrum your eyes can see) but plants love 455nm, 660nm and 420nm in that order (twice as much love in the 455nm than 420nm). So even though you are reducing par, it doesnt reduce the growing intentional, it will increase it.


That being said, they will have an effect of the color of the tank but not as much as the 455nm (455nm CREEs are just much more efficient and your eyes can see it).


Over a freshwater tank, 45g, about 10-16 @ NW 700mA would do it (without any other colors). Adding the other colors will just help with the kelvin.

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Aren't UVL super actinic VHOs ~ 420nm?

Edited by siwelk

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I have 20 Cool Whites, 10 Neutral Whites, 20 Royal Blues, and 10 UVs over my 90, all of the LEDs are CREEs except for the UVs which are Bridgelux.


Honestly, with all the other LEDs I really can't say that I can see any visual difference between having the UVs on or off, they really don't add anything color wise, as has been said you just can't see most of what they're putting out, even on by themselves they're fairly dim. At full blast the UVs light up my tank about as much as 10 whites do on dimmest setting.


That said I've noticed a slight color difference since I added them about 3 weeks ago in some of my corals that I bought online. These corals all had pictures which showed them off as being either purple or blue but when I got them were not nearly so, partially I'm sure because I don't have them under a 20k Radium. Anyways just in the last couple weeks since I added the UVs I've noticed a slight color change in them as they've gotten slightly bluer.


I've actually been using my UVs dimmed all the way down as nightlights, I like the look a lot more than blue LEDs and my green corals seem to fluoresce even more under UVs than RBs which really sticks out since the lights are so much dimmer.


Edit: Just wanted to point out that since you're proposing a 1:1:1 ratio of NW, RB, UV LEDs you're probably going to actually see a much more significant color difference with the UVs than I do with a 3:2:1 ratio, obviously.

Edited by Elem7777

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I have ran the 420nm UV leds on my tank for a year now. The ratio of leds are listed below.


5- bridgelux N402

5- Satistronics 445nm

10- Cree xpe RB 455nm

5- Cree xpe 470nm

2- Luxeon k2 cyans

13- 3w Shenzhen Weili Optical 420nm (Just figured out today the dies are the same as satistronics 1w 420nm) We all know Shenzhen Weili can be a lil shiesty


I went way over kill with the UV to truely figure out the visual and growth effects. I have to keep it turned down as it seems to piss off some of my corals. All of the colors are able to be independently dimmed (except the regular blues and cyans are on the same string). I have to say I do notice a slight visual improvement with the 420nm leds but its nothing significant. If i had to do it all over again i would still run some of the 420nm leds but not as many.

Edited by fishnlou

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