Conversion bulbs have me fucked in the head!!!

Ok so i just got a 400w mh setup off craigslist for a wonderfully low $100 and im extremely confused about what bulb i should put in it to flower and where the hell to find one of these bulbs. Im out in the sticks and it seems the internet is my only option anyone have any personal favorites or suggestions Im really not well versed in the HID lights. any help would be awsome THANKS SO MUCH!!

I like my 600 HPS the best. Is you 400 MH a dual ballast?

i have an mh setup, and i just got an eye hortilux hps conversion bulb for it.. i forget where i got it from honesstly, but it was off of the net somewhere, just google conversion bulbs and im sure you will find a decent place for them.. the conversion bulb is more in the proper spectrum for flowering as opposed to the mh that i was using for veg, and it works much better than the mh bulb did..

so ur ballast is just for mh 400w,u can find conversion bulbs on net buy hps conversion bulb if mh ballast is not switchable if it is, will have a switch for mh/hps. mh for veg and hps for flower. hope this helps