I just started putting some new hooks/seedlings under my 400-watt HPS. It appears that after 1 day, a few of them are slightly curled at the edges. So, I moved them to the perimeter of the grow area, for now. Is this simply too much light for them, at this stage? Should I put them back under the T8s for awhile, or can I just keep them at the perimeter of my grow area, which is 4x4? I raised the HPS to 24-28" away. Thanks.