advice needed

[encore]

i started my seeds in baggies, moved them to 2 1/2 x 2 1/2 x 3 1/2 inch pots, i'm using LED lights and a fan, lights on 16 hours, fan on and off different times during the day, leaves strated to turn purple, so turned heat mats under trays on,(basement was in low to mid 60's) also have a heater blowning towards the plants, (about 6 feet away, temperature of soil is around 80 degs, most of purple leaves are gone now, only watered when pots felt light, about a dozen or so plants are starting to have leaves that are drying up and looking terrible, any ideas?--- thanks tom