* 8…, …The ATI Blue Plus T5 HO fluorescent bulb combines the properties of a blue bulb with a True Actinic Blue 03 bulb. Ceramic metal halide lamps greater than 100 watts with pulse start, electronic ballasts are slightly better on all counts but should be reviewed as candidates for retrofit. T5 Fluorescent. A wide variety of metal halide ballast t5 options are available to you, such as high pressure sodium, high intensity discharge. A metal-halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides (compounds of metals with bromine or iodine).It is a type of high-intensity discharge (HID) gas discharge lamp. Is there a massive marketing scam to replace obsolete HID lighitng with new T5 lighting, when it would actually be better to replace it with new HID lighting?