LED + T5 DIY light questions

Poseidon · Apr 8, 2012

Good Morning R2R!!!

I am starting a new reef, this one will be 36x18x22, (the height is yet to be determined) and I am thinking that a hybrid set up using what I have and LED would be a good choice.

A few years ago I made this:
https://www.reef2reef.com/forums/eq.../14410-my-current-do-yourself-project-x3.html

I was thinking of doing something similar but this time I was going to use T5 and LED. My question has most to do with cooling, as most of the LED fixtures use a larger MASS of Aluminum, as a heat sink, and I am thinking of using a larger thin sheet actively cooled by fans. As thermal dynamics is not something on my current resume I wanted to ask those that would know.

Also how would this look for a layout: (+ = LED)

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3 T5 bulbs, and 2 rows of Blue LED.

Also, I woefully illiterate in the language of LED drivers, bulbs (emitters), and acronyms. So if anyone has a handy guide to LED nomenclature that would be great!

revsgirl · Apr 8, 2012

Hopefully some of these guys around here can help ya!

Poseidon · Apr 8, 2012

Thanks Tonya, I am hoping so too. I know today is a Holiday though, so maybe tomorrow...

Reef Breeders · Apr 8, 2012

Heat sinks are the way to go, there are smaller thinner ones out there, I myself have been building LED accent fixtures with 1.75"x12-14" heat sinks. You can run them without a fan for hours, and they remain just warm to the touch. A fan would have to be running 24/7 to cool a sheet of metal with leds on it.

KJAG · Apr 8, 2012

Id look to ATI t5's(and others that use a splashguard) for design reference. My ATIs run significantly cooler with the splashguard in place, due to the heat being contained within the fixture for more efficient removal. I dont claim to be a physics guy but its somewhat of a vaccuum effect if you will...Also, You may or may not even notice your leds while the T5s are on, depending on what bulbs your using. I run T5s but also have a Unibody fixture with a gooseneck mount on my tank,( only run it when t5s are off.No whites, just Blues and Violet. Strictly Aesthetic) , but when Ive turned both on the LEDs are easily overpowered even by two T5s. Hope this helps.Also, fin size on the heatsink doesnt necessarily mean more efficient cooling. My unibody has tiny fins and it runs cooler than any of my other builds using the standard heatsinkusa sinks. Again, its due to the splashguard.

Poseidon · Apr 8, 2012

I guess what I really need to know is how does a heat sink that weighs X with the dimension of 12"x6"X2" differ from a sheet of aluminum that also weighs X but has a dimension of 36"x24"x0.050".

As for the cooling, you are correct, the ATI fixtures do work very well. I had several of them at Reef Paradise when I was running the shop. The fans are tiny, and move far less air then the IceCap fans did in my fixture though, and in my fixture, I was actually using the reflector/clips as a heatsink on the bulbs, drawing the heat away from the bulbs that way. I am unsure if it was as effective as having the splash shield would have been, but in that fixture it was really my only option as I did not plan for the shield to be part of the cooling. A shield would have trapped hot air below the bulbs and reflectors, with no where to go. In my next fixture, I will not make that mistake again.