leds help

I just order 10 royal blue leds from rapidled, i am going to put them on a 48" section of u-channel, i also ordered the 4 led moon light kit i was wondering if i need to have a fan on them or if the u-channel will dissipate the heat enough? what do you guys think?

 

I think you might be fine. It may be depend on how hard you drive the leds. Did you go with a dimmable driver or a constant current driver?

 

i got the dimmable driver, from my experience on my custom led build on my biocube tank i wont drive them at full current. it all really depends on how much they will get washed out on my 75 gallon tank. will the thickness of the aluminum u-channel have a big effect on heat transfer? if so should i thicker or thiner

 

Thickness doesn't have a huge effect (it's a secondary effect really); what allows a heat sink to work is convective heat transfer. Therefore it's surface area that is of the utmost importance.