I have in my smaller closet a 400watt switchable ballast, when i have the hps bulb in and the ballast is switched to hps there is no buzz or any problems. when i have it switched to mh and it turns on the ballast is extremely loud until the bulb warms up and when the bulb is warmed up the light seems to flicker... it never completely turns off or anything just hasa steady flicker to it anyone know what causes this? what remedies there could be for this and if this is a fire hazard or could make my bulb explode?