the HPS bulb (brand "Artemis") that came with my ballast/reflector and everything makes a really annoying whining noise at random intervals so i've decided to invest in a different bulb. any specific one that's better? the ballast is digital and takes both MH and HPS bulbs if that makes a difference. as of now i was looking at the Sunmaster 250w dual spectrum HPS bulb, apparently it is digital ballast friendly and it's also reasonably priced. anyone have anything to say about these lights?