Double-whammy lighting/heating energy saving tank hack

Flickr user fotogra4er replaced the fluorescent tubes lighting his aquarium with LEDs. Which, of course, make way more light and way less heat for the same amount of energy. Then he upped the ante by cooling the LED lighting bank with circulated tank water, exploiting what waste heat the LEDs do generate to warm it, and thus saving even more power that would otherwise go to the tank heater.

[via Hack a Day]