For my fresh water tanks I float freezer bags of ice cubes on the top. When it gets really bad a water change will help. I keep the lights off too. I have never had a problem doing this. I will try the fan idea.This is gonna be a long hot spell! _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member