Drop your lights further. That will raise temps, which in turn will drop %RH in the area right close to the plants, and create conditions not conducive to pythium fungus. It will also solve your stretch problem. You should be within 2" of the canopy running tube flouros. Jsut keep an eye on vertical growth and watering- they should not touch the bulbs, especially T8s (T12s are cooler to the touch), and if they get totally dry they CAN scorch.
Find the happy medium!
Edit: make sure you have adequate air movement- they should be warm and dry-ish, not hot and arid. Again with the happy medium.