What type of lights do you have? I am assuming some sort of LED's because of the dimmer. If so, just an FYI, dimmer switches are useless. Your plant from a seedling can most likely handle your light at max output, even seedlings. DO NOT UNDERESTIMATE HOW MUCH LIGHT THESE THINGS WANT. With that being said, heat from lights can and will cause damage and if they are too close can cause bleaching. So just keep them at a safe distance and you will be good. Also remember Increase light= increase in photosynthesis = increase in nutrients. Basically, if you drive them hard with light, they need more everything to keep up. You can check out my beginners guide to LED's in my signature if you want more info or are stoned and bored lol.
I hope it can help in a small way. I started on these forums around 2 years ago and there are some really helpful people here. Some of them are modest some are arrogant lol, but never in a "you suck" type of way. All in all, its a really great resource for new growers and cool place for old timers to hang out as well. I hope you enjoy your time here and feel free to hmu if you need anything. Except for soil, never touched the stuff and cant stand it. If I wanted to do soil Id move to outdoor grows ha ha! 
