Good morning, good afternoon, good evening, friends! I'm Tiger from India. I have devised an easy-to-make, extremely bright (~4500 lumens), energy efficient (just 45 Watts) lighting for your planted aquarium for under $5, powered using a spare computer PSU. This lighting system has a very long life of >50,000 hours provided you make it correctly as shown, and the LEDs do not overheat. It would take you around 45 minutes to 1 hour to do it, and years to enjoy it.
Commerical LED lightings can cost upwards of $150, and aren't nearly as bright as this one in the tutorial. This provides your planted tanks with metal-halide-like brightness, although not heating the water up, or making a hole in your pocket. In a 15 gallon tank, you'd get a fluorescent equivalent of 4-5 Watts per gallon of light.
Another big advantage of this lighting over most commercial lightings is that you can control the brightness of the LEDs by using a 12V LED dimmer that costs less than 1 dollar.
The best part about these PWM dimmers is that they do not lose any power to heat. So if you are at 50% brightness, you are consuming 50% electricity, and generating 50% less heat. LEDs are also more efficient when they are at less than full power. Two points to energy efficiency.
All parts can be purchased on Amazon/eBay, except the 2 feet aluminium channel. It will be readily available in shops that make window panes and fits them in buildings.
So, here's to metal halide brightness, minus the heat and plus the extremely high energy efficiency!
And minus the lots of cash!
Detailed instructions in the YouTube video.