He (Steve) is sure that his heat sinks are good.... may be if canopy is too tight there is not much air flow, thus it will be harder to keep low temp.
Anyway here is what he says.


Tubular Heat sinks are SUPERIOR!

http://stevesleds.com/Tubular_Heatsinks.html

This is one of the primary challenges with providing a proper heat sink for your LEDs -> Keeping them cool all while being lightweight and affordable. Generally, there are two mainly used heat sink styles, the plate-style heat sinks and the tube-style heat sinks.

Everyone has seen those old-fashioned "plate" heat sinks with fins sticking out on the back. I think that people currently use those because that is what they have always used and it seems to work ok. That is what their dad used, and their dad's dad used....you get the idea. Yes they do work just "ok" but that is it. Plate heat sinks are heavy and expensive and don't work as well compared to tubular heat sinks. You have high performance LEDs, why not get a high performance heat sink that costs less!

There are 4 properties that heat sinks need to be effective at dissipating (getting rid of) heat.

1) Thermal conductivity
2) Surface area
3) Air movement over that surface area
4) Affordability
.

His tank with LED DIY fixture
http://stevesleds.com/Photos.html
.
Cool White MSDS
http://stevesleds.com/uploads/Luxeon...eve_s_LEDS.pdf
Royal Blues MSDS
http://stevesleds.com/uploads/Luxeon...teves_LEDs.pdf
.

Mike's LEDs, 27 no name 10 watt multichips mounted on individual heatsinks with fan attached to thin aluminum angle. Mixture of 6500K white, 10000K white, blue & royal blue.

Lightweight & been going strong for over 1 year. I've had to replace a few of the fans, they're quite small and cheaply made, but the price was right & I have plenty of spares. I understand even high end lights like Radions have had some fan issues, so.... I can live with my cheapies. But I'm considering a top for my fixture which will include a couple of larger, heavy duty fans. Might be able to ditch the little ones then, since that's 27 fans for 27 LEDs.


https://ojcrhq.blu.livefilestore.com...48e.JPG?psid=1

A few months ago I added a couple of 5050 SMD RGB strips along the center rail of 10 watt chips. Works great for dawn/dusk.

https://ojcrhq.blu.livefilestore.com...61e.JPG?psid=1

A plate heat sink with fins is not old fashioned and is superior to a tube. It has way more surface area and can accept more convection. Those are really the only two variables here.

Ditto!

Heat radiates up......naturally without mechanical requirements.

How does heat dissipate using a square tube? Must require mechanical intervention. What happens if the pressure fan fails??

What happens

Each scenario has its pros & cons. Set ups with fans need the fans to work, or else. Set ups with large heatsinks & no fans are heavy & tend to be overbuilt to ensure there is sufficient mass for cooling without fans. You can also hybridize with a moderately sized heatsink and a couple of larger fans to move air over the heatsink. Not many people actually do the math as to how much heat each LED produces & what is required to sufficiently cool them based on the actual mass of the heatsink without fan. Some folks go as far as installing temperature sensors to control fans. That gets a little more involved & complex for the average DIYer. As far as the tube set up, a fan blows into one end of the tube & as the air moves along, each LED adds heat & the one(s) at the ends of the tube(s) will tend to benefit less from the air flow since that air is already heated up from the LEDs upstream. Works fine for a shorter run of tubing, but a long run could spell disaster for the LEDs at the end of the tube. All depends on your particular needs & preferences.

Temp sensors and a FET on each of my heatsinks operating the fan's. But then ya, I'm not your ave DIYer LOL