correct me if i am wrong, but smartlite is a pc, and same type bulb as power compact, except it's 50/50. i replaced my smartlite with an old one i had for 1 year, put it in the back, and middle has a 67k white bulb, and front actinic. the new smartlite bulb actinic side is darn bluer than the front actinic i have, which was just purchased few months ago. it sure is very intense and bright now, just don't know how long the blue will hold.