Well, two plants under 315 watts would be a more realistic figure, and you'll be able flower with that, too.

I don't know your plans on the flowering, but depending on the strain, you can yield anywhere up to just under a QP with that much light. Shit, you're producing more wattage than I am at 315 solid watts.

But then again, all I use is a 150 HPS and a few Fluorex CFLs.

[ Envirolite > Fluorex > Regular CFL ]