After quite a bit of experimenting I've finally found a winning solution to light my aquarium with Luxeon LED's. These are the 5W LED's that generate a lot of heat which must be dissipated.

Starting out I knew that I'd need heatsinks to keep the LED's cool, I didn't realize just how much heat these LED's put out at full power.

My first idea was to use a flat piece of metal and mount the LED's on the bottom and mount the heatsinks on the top. The heatsinks had some thermal paste put on the bottom and then had contact cement around the outer edged.

The LED's were put on a similar way. A small dab of thermal paste in the center with a couple dabs of contact cement along the edges.

The problem with this setup was the hot spots that were created. The heatsinks worked perfect as they pulled all the heat away from the LED's that were close to them, but if the LED was more than 1" away that part would get very hot... and the LED burnt out.

After burning out a couple LED's I decided that they should be mounted directly on the heatsink. This would allow for much better heat transfer although I'd be able to cool less LED's per heatsink this way.

I'm using ordinary computer heatsinks which were designed for the AMD K8 although any heatsink with a large base will do.

Initially I had used contact cement to attach the LED's to the heatsink; however, this isn't a good idea! Only some of the LED's were electrically isolated and some of them blew up again (this was getting expensive!).

My last and final design uses thermal tape instead of contact cement. This ensures that the LED's are electrically isolated, but they can still transfer their heat to the heatsink. The reflector is actually a PVC end cap for eaves trough down spouts. The heatsink is glued on with black silicone (don't use white... these things will shine right through it). On the inside I glued some aluminum foil.

Pictures and vidoes will be coming as soon as more testing is completed because I'd rather you not have to burn any of these expensive LED's out.

So far they've been on for a week with no side effects so the full how to should be up soon.