@lopenator
do not fight with sunni ....she is trained in the ways of a social worker so she know mind tricks (think of a shrink that knows the paperwork/red tape of government and u got sunni)
and she is right alot of what u are asking is repeated in here every 2/3 weeks ........we have no trouble helping someone out but u got to do little leg work and think about stuff before hand
the answer is the HPS/MH bulbs take a E39 socket
now as for ballast 2 types magnetic and digital .......u want digital as magnetic are getting phased out
when u shop for a ballast u want to look for what features
crash course
1 dimmable ballast are bad (they lower the power going tho the bulb witch alters the light waves and shortens life of bulb ) talking the ones in power 100% 75% 50%
2 Select a watt is the one u want it allows u to use the bulbs at the correct power 400w 600w 1000w .....so if u get a bigger area u can use a bigger bulb with out investing in a new ballast too
3 they have changed bulb types there is now a single and double ended bulbs ........invest in a ballast that does both
4 once u have the ballast u get a hood the hood just needs to match the ballast plug (normally S plug) this is where the single / double ended comes into play
5 never buy a used ballast unless it has been checked out by a shop that repairs them (ballast have a run time at some point it fails i know magnetic can be rebuild not sure about digital ) ....so best to buy a new one get full life out of it