Hi all I just got given a low bay 400w hps with square built in reflector looking at bulbs my one has the old school round style bulb just wanting to know if I have to put that same style of bulb or can I use the newer longer style hps bulb View attachment 1513465
you should be fine with any 400w hps bulb...as long as it's not like a digital ballast type specialty bulb or something. Just make sure a larger bulb will fit in the hood also.