ok as I've been reading advertisements and threads I've read that some need "additional ballast" or that a light might need to be converted..what does this mean to me? I'm basically trying to find a decent probably 400w HPS light for growing
Well smoke if you live in a fairly metro area I would personally recomend that you find an electrical supply store, purchase your setup there (usually about $100) and convert it to a remote ballast system (another 30-40). It is very easy to do and will save you oodles of cash you can spend on other things like nutes or good stable seeds.