I've been running some lunar link moon lights on my tank for a long time now, but some of the leds are pretty dim and seem to be burning out. I am planning on replacing them, but figured it would be cool to make them dimmable via arduino at the same time. I'm thinking of using the PWM on the arduino to transistor to control the power to the LEDS. They need 6vdc according the transformer so I suspect the arduino can't power them on it's own, thus the transistor connected to the transformer.
Is that similar to what you're going to be doing for your leds? I know you'll be working with a higher wattage since you're controlling the main leds and not just moon lights, but I was curious to hear how you planned to dim them with the arduino.