metal halide mh bulb flicker

Hey guys I recently bought a grow lush tent and light kit for $215 bit of a bargain 250 watt setup and 0.5x0.9x1.6 tent. With 4 1 month old babies in it until sex is shown. Anyways I noticed that the start up of the mh bulb is dodgy flickering and coming on and off and once warm has a very slight flicker to it, its hardly noticeable but still notice able. Just wondering if this is likely the bulb or ballast and if the flicker will affect the plants.
Cheers, sniffmybuds

crappy bulb

at least that was my problem