PPFD for growth

[katpurdy]

what is the lowest PPFD that is determined acceptable for growth? I currently use 2x 250W 10K xm SE bulbs. I know that the PPFD for this bulb on an electric ballast( i use PFO) is about 115.

If I wanted a bulb in the actual color range of say 12-14K...what is a good one and still get growth? In my head it is hard to go to a bulb with a PPFD of 80 or less in order to get the color. PLUS!!! I don't want BLUE...I really want a crisp white...to have an authentic look to the corals...not to flouresed(SP?!)


Thanks