Quote Originally Posted by Sativagrowin
That would be just fine but remember that that link was for just the bulb and not the whole light. To run a 400 watt HPS you need ballast. Youll be lookin at spendin around $175 for a cheap unit.

Laterz
He's right. Also, the CFLs would add to the growth in yield if they are 5000Kelvins or higher and they'd contribute more to flowering if they are closer to 2500K. Either one would contribute to both in some way or another. They are especially good for the parts of the plant that are not getting any light for any reason. I remember when HARDDON was showing that grow that he got off the internet. The guy who grew them started getting much better undergrowth once he put the CFLs underneath the plants.