I don't know whats wrong with my 600w lighting system. It keeps blowing my 600w bulbs but not the 400w bulbs. Anyone else ever have a problem where bulbs keep blowing out? The 600w bulbs wont last one day. They blew by the following "on cycle". I have it on a 15amp rated timer. I never had a problem with my 400w system and my 600w ballast w/ 400w bulb are fine as well.