Lights were on in both tanks for about an hour yesterday before the reefkeeper's turned them off on both tanks. Temps still stayed around 80 until about 9pm. I have a huge west facing window, so morning - mid day is fine, around 18:00 the 'ish hits the fan and my place gets uber hot. Tonight I'm going to rig up one of those huge floor fans to trigger with one of the tanks temp settings.