fresh water lighting

hi all i know this is a reef forum but you guys seem to be at the leading edge of led lighting for aquariums so i will ask my question here.

i am doing research for a new tank i will be building in the next six months or so. i will be doing a plywood aquarium build with an integrated behind tank sump. the tank dimensions are 55.5" long 24" wide and the lights will be 27 inches off the the substrate. the water will be around 4 inchs below the lights i may make this distance taller if needed we will see. I have been looking at the bridgelux leds from; AquaStyle Online. my thoughs are to use four, three led clusters distributed down the center of the tank. my plan is to mount the three led's to a 4.7"X4" heat-sink. the leds will be mounted 3/4 inch off the corners on one edge and one centered on the opposite edge thus creating a triangle on the heat-sink. i am planning on equally spacing the clusters along the center line of the tank. alternating the triangle points. i am also thinking about using 80 degree optics. also i am planning on using a meanwell driver for the lights.

do you think that this would be enough light for my tank? i will not be growing anything in the tank so it would just be for light.

 

That's probably enough leds to light that tank, but with the configuration you want, I'm almost positive you will have spotty coverage which may or may not be the look you want. Raise the lights up to 12 inches above the surface and you should get good even coverage.

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thanks for the info. do you think it would be ok with out optics? i may make the hood taller we will see

 

I have the Aquastyle LEDs. I don't think 12 is going to be enough for such a large tank. These are not miracle mini suns you know. That close to the water with optics you are going to get sort of cones of light at the top. The beauty of LEDs though is that you can just add incrementally. If I were you I would start with at least 24 evenly spaced. You should really look into the color though. 10K LEDs he sells make the tank look a little strange. I am not sure what you are looking for in freshwater. More yellow?

 

i am looking at a nice florescent cool white look for the tank. i have found that i like the 6500k look that i have on one of my other tanks i have done some simulations in google sketchup of the lights in my arrangement with different optics and i found that with 80 degree optics i should get a fairly even distribution of light in the tank i may get one of the 24 led kits and distribute them and see how i like it.

does anyone know if you can just get one color led in the kits from them or would i have to buy them individualy

 

I didnt think about it, but yeah I would agree with you. I was kinda thinking about 12 crees, not bridgelux.

 

so your saying that 12 crees would do the job? i have found crees for 4.50 per bulb here CREE XP-G R5 Cool White 3W LED on Star
i was planning on getting meanwell drivers anyway so i will come out at about the same cost if i go with the crees over the bridgelux.

i e-mailed them and they said to use them without optics if i have the bulbs 4 inches off the water. i have toyed with making the hood 12 inches tall and then the lights will be about 13 inches off the water and use the 60 or 80 degree optics

if i were to mount the crees individually how big of a heat sink would be required and would i need fans on them?

 

12 LED's over a 55 inch tank is going to be spotty or leave most of the tank dark depending on how you arrange them. Since this is just freshwater wouldnt it just be easier (and cheaper) to go with t5's. I was going to use the 12 LED set up over a 10 gallon tank before I went with a different tank.

Also bridgelux LED's are pretty good, I dont think CREE would make a difference...this is a coverage issue not an intensity one.

http://www.nano-reef.com/forums/index.php?showtopic=267432

You might want to try this method out...it seems pretty cheap and effective even if its a little ghetto.

 

If it is going to be fish only then a single 48" fluorescent bulb will be plenty or the LED plan without optics. You will need enough light for you to enjoy your fish. I would also use a bulb or LED in the 5000K range or a little lower to enhance the fishes' colors.