With the size of my space being so small, i should be safe with one 250w MH bulb for veg and one 250w HPS for flower, right? Are these going to kill my electric bill? Also, I've been having some trouble finding out what ppm is, some way of measuring nutes i think. If anyone could help that'd be great.
EDIT: I just got off the phone with the owner of my local hydro shop. He informed me that not having at least one 400W HPS bulb in the flowering stage may produce weak buds. Truth?