This unit is actually a rebuild, as after a year of exposure to salt water spray has corroded it badly. The rebuild procedure however allows me to look at the light as if it were a new project.

the heat-sink is fitted into a plexiglass carrier that covers the baffled refugium area set aside for macro-algae fairly well.

I first drill holes to hold the carrier boards. I had used epoxy, but it doesn’t bond well to aluminum. The tapered heads of the screws work better in maintaining good contact between the heat sink and the carrier boards. Note how the heads of the screws overshadow the pads. Care must be taken when soldering to avoid shorting the power lines. Typically the LEDs come on the carriers, but the carriers can be purchased cheaply in bulk if needed.

for this project I’m using 4x 6500K 1 watt LEDs and 6x 10000K 1 Watt LEDs.

Drilled and tapped

Mounting the carriers sans LEDs

I solder wires to the pads in a series configuration. This means I go from positive to negative all the way around the carriers are oriented with the first 5 with positive to the top, and the next 5 with positive to the bottom. As the power supply is a constant current model I can have up to 12 or as few as 8 1 watt LEDs daisy-chained safely.

Soldering the power wires

halfway done

Wired up

Adding some thermal paste. This is the cheap stuff, but it’s all that is needed for this application. Save your arctic silver for your CPU

Installing LEDs, note the tiny little negative (-) marking on one side when soldering.

I’m using a constant current power supply I bought on eBay. I’ve mounted the power supply on the side of the heat-sink, and have grounded the AC input to the heat-sink itself. The heat-sink is massively over sized for this project. I have used 1/8" thick aluminum with no excessive heat in the past for a 20 watt lighting fixture. It did get a bit hotter than I liked, around 95 Fahrenheit and I had this material available so used it.

The big advantage of buying a driver is that it’s waterproof also

Note the ground lug

While you can make your own power supply, these units are very cheap, and have short circuit protection. Used in combination with a GFCI outlet they are very safe.

I’m planning on adding a spray shield, and adding new lenses as well in the near future. I’m hoping this rebuild will give me more than a years service. It has already paid for itself however, as this 10 watt unit has a higher output than a 65 watt CFL bulb, measured at 12".

Here is the unit lit, very bright as you can see and draws very little power too.

Just under 1000 lumens

Once I have the lenses mounted I used a hot glue gun to seal the LED carrier to the lenses. The lenses don’t fit very well with the wires in place, much less the screws I used to mount them. That makes this step almost mandatory if you wish to use lenses. As the last picture shows, the lenses make a huge difference in focusing the light The ceiling is about 8’ at my workplace.

The hot glue sealing the solder joints away from splash

The difference between with and without lenses is noticeable

These particular lenses have a 20 degree focal width. You can buy them from 10 to 90 degrees however

The lenses let you get every last little bit of light into a useable area, rather than wasting it, or losing lumens via waste from a reflector. For a reef tank, where depths can be up to 30" and high light levels are a must LEDs are great. They can have the same output levels as a metal halide at a fraction of the heat and power draw. Assuming the LEDs are of a high quality you can get years of service out of them, and save yourself from needing a chiller as well.

I’ve dropped my power bill about $5 a month by converting my tanks to LEDs. Once the reef LEDs are in place I expect another $5 drop, balanced by the fact that the heater will actually turn on once in awhile now. My current 8x T-5 bulbs push the temps to 82 degrees daily. In the summer the temps can peak at 85 even with an evaporative cooler.