O well.

I'm obviously not homehydro, but will tell you what I used; I hope others will also offer some suggestions(including homehydro)
Google "5-11-26 Hydroponic Special". It's mixed with Calcium Nitrate and usually epsom salts (magnesium sulfate) for a quick easy general fertilizer.
Scotts makes it, it used to be called Hydrosol I think, now 5-11-26. Southern Ag makes a version of it, as well as hydro-gardens/chemgro.
Find somewhere by you that sells fertilizers and they can order for you.
Hope this helps.