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View Full Version : How many LEDs


Saadatski
07/15/2011, 02:52 PM
i am getting a 75 gallon 48" long

how many LEDs would i need to grow SPS. a 35" heatsink good too?

Saltwatercoral2
07/15/2011, 02:57 PM
I would get 2 smaller heat sinks. I have seen as many as 36 leds to 96 on a 75. If It was me, I would start out at 48, and if your lacking, i would add more. This is what i plan on doing anyway.

Saadatski
07/16/2011, 07:39 PM
so 48 would suffice my 75 gallon for SPS?

James77
07/16/2011, 08:53 PM
so 48 would suffice my 75 gallon for SPS?

Yes....although always leave open the possibility of adding more. I run 77 on my 120g (4x2x2) and it is too many. When I redo it, I am going for about 50-60 using 55 degree optics. I run mine currently at half power, and it is very bright. Ive run them for a month, and the corals look as good as they always have.

I agree with ^^. I would do maybe two samller heat sinks. Another thing you can look into is channel aluminum( shaped like a U ). I used 1/8" thich, 1 inch wide, and half inch high for mine. It allows you to space them the rows to your liking as well as cut down cost and weight. Works just fine as the thick sinks for heat removal.

My thread with them. I have yet to update it, the light has been running for a while though. I may be re doing it all to spread out the LEDs more and cut the number of them. I unfortunately went with rows of white and blue instead of alternating, and i have banding.

Felixc395
07/16/2011, 08:55 PM
Just make sure they're cree's or another high quality manufacturer. I have a 75 gallon, two AI modules coming on tuesday. So that's 48 LED's right there. With 48, no optics would be best and mount it close. Or you could use 70 degree lens and hang them higher.

James77
07/16/2011, 08:56 PM
so 48 would suffice my 75 gallon for SPS?

so 48 would suffice my 75 gallon for SPS?

Yes....although always leave open the possibility of adding more. I run 77 on my 120g (4x2x2) and it is too many. When I redo it, I am going for about 50-60 using 55 degree optics. I run mine currently at half power, and it is very bright. Ive run them for a month, and the corals look as good as they always have.

I agree with ^^. I would do maybe two samller heat sinks. Another thing you can look into is channel aluminum( shaped like a U ). I used 1/8" thich, 1 inch wide, and half inch high for mine. It allows you to space them the rows to your liking as well as cut down cost and weight. Works just fine as the thick sinks for heat removal.

My thread with them.
http://reefcentral.com/forums/showthread.php?t=2027482&highlight=channel
I have yet to update it, the light has been running for a while though. I may be re doing it all to spread out the LEDs more and cut the number of them. I unfortunately went with rows of white and blue instead of alternating, and i have banding.