Merrill,

When I used MH lights I had 400W agrosun bulbs. I tried to keep the bulb
about 4 feet from the plant directly beneath it. Remember that as you get
away from the center the intensity drops.

A 400W bulb 4 feet above the surface would create a primary growing area of
4 x 4 feet. There is an additional foot around the perimeter that would be
find for lower light plants such as paphs.

When I put the bulb on the light track I would move the light a foot closer
to the plants since it was constantly in motion.

When I did this the Phals did quite well.


Gene