maybe this will help some.just set up new lights and learned a lot from posts and a couple of electrical experts.i picked up some 400 watt fixtures without ballasts.got lumatek lk400 digital ballasts from bigtomato.com just under 500.00 for 4 shipped.these will fire hallide or hps and with dimmable bulbs from e-conolight.com-less then 10.00 shipped i can switch back and forth 250 to 400 watts by turning a knob.i can run hallide or hps depending on conditions.plus these can be switched to super lumens with the turn of the knob and get 10% more light at 250 or 400 watts