No it it does not have to be a pendant but I was thinking that way for MH so that I could try to keep as much heat out of a canopy as possible. I know the magnetic ballast are better because they tend to overdrive the bulbs producing better numbers. What I saw on sanjays site was the the M80 ballast where running the 250w bulbs at 315w-325w. I am a little worried that this might be a little too much light. I know Anthony Calfo is a little conservative in his lighting but I do trust his knowledge and with that he recommended 150w HQI. So needless to say I am a little confused here.