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Reef Mag » The Hardware

The Hardware

Here are the components I will need to decide on:

  1. LED
  2. Heat Sink
  3. Constant Current Driver
  4. Power Source
  5. Optic
  6. Swivel Mount.

So first up the LED. It has to be as powerful as possible per die and pre-mounted to a standard 20mm star. The new Cree XP-G single LED dies are very attractive. Very efficient and can emit 345 lumens @ 1A. Still not as much as a multi LED (4 LEDs on one die) Cree MC-E however which hits 752 lumens at 2.8A. The other competing multi LED was a Seoul P7 which was very similar to the Cree – 4 LEDs on one die and 2.8A max current. The seoul also produced more lumens – up to 900 – on some BINs (each LED is labelled with a BIN code which states it’s production qualities – they vary). The other big plus for the MC-E is it’s fantastic thermal efficiency @ 3°C/W (lower is better). For comparison the XP-G is 6°C/W.

Cree MC-E:


Seoul P7:


Although the Seoul was more efficient unfortunately it turned out to be very hard to source pre-mounted on a standard star mount.


Furthermore I managed to source the MC-Es pre-mounted on stars much cheaper. So the choice was easy.

The constant current driver and the power supply. In the past many people went with the buckpuck type driver which would run 6 or 7 high power LEDs in series. Then you could source a DC power supply for say a laptop – typically up to 24V at several Amps. The buckpucks were often available with dimming capacity.

Fortunately time has moved on and Meanwell spotted an opening in the market for an all in one constant current driver and power supply with either no, PWM or 1-10V. 1-10V, yipee, that’ll be sold to the man in the shoulder length waterproof gloves.


Optics. One of the most important components of this design will be getting the beam pattern and spread spot on (pardon the pun). With the fixture being nearly one and a half feet from the water surface and three feet from the bottom of the tank quite a narrow beam will be required. I also hate light spill so predominant with flood type fixtures like T5s. So I want quite a tight beam.

The only way to really decide was to order a number of lenses and reflectors and plug and play. So this is what I did and here are the results.

13.5 Degree Fraen Reflector:

13-5-fraen 13-5-fraen-beam

Carclo Optics 20 Degree Clear:


Carclo Optics 45 Degree Frosted:


Carclo Optics 44×23 Degree Elliptical Clear:


Overall I really liked the reflector as opposed to the optics. The downside was that they would offer no protection to dust, dirt and condensation to the LED itself. Maybe not a massive concern but I like the easier mounting of the optic and the fact it encases the LED. The reflector would almost certainly be hard to mount onto the LED package after the wires had been soldered.

The issue with the optics was that the narrow 20 degree optic was clear and clearly reproduced the 4 LEDs on the MC-E die. Not attractive. Luckily Carclo, the makers of the optics, had just designed a slightly large optic (26.5mm) that came with a 15 degree variant in frosted. I ordered a sample and it turned out to be perfect. Then a whole tray… here they are:


It produced a very tight beam with little spill and no reproduction of LED layout pattern. Ideal.

One Response to "The Hardware"

  1. JafT says:

    This series is getting very interesting, I’m also going for LEDs in my next tank. Right now I don’t have the time (and money) to start the project, so I will be checking yours for updates.
    Your ideas are very similar to mine, your experience will be very helpful, so thanks for letting us know how everything is going.

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