I like to keep air blowing gently on the plants after they're about an inch tall. The motion in the stalks and leaves from the breeze stimulates them and promotes stronger stems (or so I read). It seemed to work for me the last time. The powerstrip will distribute power to these:

250 watt HPS
2 heating pads (under hydroponic resevoir)
an air pump w/ airstones in the resevoir
the fan I just installed
the hydroponic sytem pump