I agree with Jorge and GrowinGreen... as long as it's properly cooled, you can never have too much light, but there might be areas that are warmer than others on the hoods and while it may not be hot enough to start a fire, it might scorch the tops of the plants. I start to move my lights up incrementally once the leaves are actually touching the glass, but only by an inch or so each time so that the lights are still as close as I can possibly get them.