i went from a 400w metal halide to LED and couldnt be happier. less power, less swing in PH in the day/night times and less heat issues. with that said, like Aztec said, the color did change, but for me my growth has spiked with the LED. Halides were good and i had t5HO prior to the halide... IMO people r dumb with LEDs and without a dimmer you're asking for issues. switching from t5 or halide to LED needs a dimmer, its a different spectrum and light penetration. Put the LED on low, feed corals more often and get them used to the light, then increase it over a 1-2 week period and viola. Thats what i did and sps, lps and softies all loved it and stay open from 2 minutes after the led turn on until 5 minutes after the led goes off... havent seen brighter colors and faster growth under any other fixture IMO