Are metal halide bulbs supposed to fire up immediately or do they take a couple min to reach full power? I just bought a dual 250 watt PFO mh ballast, I have hamilton 250 watt, 10,000k bulbs. When I flip the switch they just start out really, really dull. After a min or two they start getting brighter. Sometimes they dont even get brighter, they just stay very dull. Any ideas?