Quote Originally Posted by Kmakok
Btw this will be complicated cause some are indicas and some ares sativas so the *head* WONT be equally high
Use bricks, cinder blocks, boxes, books, milk crates under the pots...to adjust the canopy to form a bowl-shaped canopy. (shorter plants directly under the bulb, taller ones twords the outside)

The 250w only has an effective range of 18 to 24 inches, doesn't it? The 400w has an effective range of 3 feet or so. Big difference, unless you only want the top 25% of your plant(s) to get usable light.

The extra electric cost is offset by better and possibly quicker results. (more available energy per day, on more of the plant)

Lighting distance: place the back of your hand up twords the bulb. How close can you get it without discomfort or pain? This is approximatelly the closest distance to canopy. Distances vary with types of bulbs and fixtures, wattages...