LED Nano Pendant from the Ground Up

I'm gonna do it. I'm going to build a LED fixture for my 10g Tetra Half Moon that will grow any coral that I want to put in there. This isn't going to be a retro fit or a mod to an existing fixture. I'm building everything from the ground up out of raw materials. Including the fixture housing and power supply casing. I've been reading everything I can find on LED technology for over two months now but just out of curiousity for the most part...until I decided I want to turn my Mantis tank into a nano reef that a mantis lives in. But because of the odd half cylinder shape of the tank I wouldn't be able to effectively or asthetically add supplemental lighting to a clamp on halide so LED is my obvious only choice. I wish I had added all of those articles and threads I searched in the past couple months to my favorites folders.
But I have recovered a good amount of them and have spent literally hours the past three days pouring over build threads, data sheets and hardware websites. I've got enough info now to at least be dangerous lol.

So heres the plan. Tentatively it's going to be a pendant mainly because to date I haven't been able to locate an clamp on adjustable arm that isn't made of a metal that will rust and/or corrode. The casing will measure
9.25" X 6" X 2.5" and be built from black acrylic. It'll have a removable clear acrylic splash guard. Both ends will be slotted to allow a 120mm fan to move air over the heatsink. One thing I haven't figuired out yet is will it be better to have the fan pull air thru the fixture or push air into it?
The heatsink will fit snuggly side to side and end to end but have a 1.125" space above the fins to allow for air flow.
I'll be using 12 Cool White Cree XR-E's and 12 Royal Blue Cree XR-E's. They will be driven by 4 1000ma BuckPucks. 2 of the 6 light strings will be dimmable. Because I want to be able to implement timers for dawn/dusk I will be using 2 24v 6.5A powersupplies instead of just one. I will build the casing for these as well. It'll also be air cooled with another 120mm fan. Both the fans are 24v, move air at 86.2 cfm with only 19db. They'll be controlled with a 0-100% 3" controller. It has 2 temp probes, a programmable alarm and a LCD temp display. The casing will also hold the 4 pucks. The fan controller and dimmer switches will be mounted onto this too.
Well that's it for now. I won't even start ordering the parts for another week but wanted to get this thread started now in hopes of advice and ideas. I'd like to see it become a go to thread for DIY LED lighting so nothing will be done without pictures and detailed information.

 

sounds like an interesting project
For the fan I would suggest mounting on the top in the center of the fixture and put vents on the left and right sides of the fixture. Have the fan draw the air up and out the top so the fresh air enters from the sides and cools the heatsinks on the way to the fan.

And remember....

 

are those the 3w?

 

Oh there'll be tons of pics. I haven't even started ordering stuff yet. I'm gonna get the heatsink and the ABS acrylic first so I can build the fixture. ;D
I planned on the fan being to center. I just didn't know if it'd be better to push or pull the air thru the fixture but you confirmed what I suspected so that's figuired out now. ;D;D

 

Yes they are.

 

I'll be following this thread.

I've been looking to make a LED fixture of my own.

 

If I do it right it will out perform a 450 watt MH at 100%. If I blow it I'll have a real expensive night light. ;D The estimated cost is under $400 to build it so that's not too bad.

 

you know not to drive them at 100% right?

 

I've spent all my time reading building it. None about using them yet so no I wasn't aware of that. Why might I ask? Maybe your answer will save me some money on pucks.

 

Your LEDs wont last nearly as long at 100%