I bought a led light kit from lowes. It came with a sticky strip that contains the LEDs. I just stuck that to the inside of the reflector on my aqueon lights beside the fluorescent bulb. I use it on a timer as a blue night time or moon light in conjunction with the fluorescents during the day. You could just add more light strips to the reflector if one is not bright enough. I'm not sure how well it will grow plants though. Or you could try reducing the amount of time your light is on. Also if it's in direct sunlight from a window that could also be a cause.
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