I recently upgraded my old 4' T8 dual bulb fixtures. I ended up picking up a Hydrofarm T5 HO EnviroGro 4' 8 bulb fixture and filled it with AgroMax T5 HO 6500K bulbs. I've noticed a pretty obvious increase in brightness and heat from the upgraded fixture. Most of the seedlings seem to be responding very well to the new fixture. That being said, I am starting to notice a little bit of a purple color on some of the seedlings:
I am thinking that I may have had the light fixture too close. It was at about 4" over the top of the seedlings which has now been bumped up to 6". Also, the other night I believe that I accidentally flipped the light timer switch to manual so the lights were on overnight which probably didn't help.
Does anyone have any advice on distance with T5 HO fixtures? Am I missing anything? I appreciate everyone's help in advance.