you actually want a 10-15 degree drop in temperature when the lights go off, it gives the plant a "break". above/below this, your plant is going to use stored carbs for maintaining homeostasis (idk if thats what it is in biology)
what i'm saying is it will have to put effort into regulating itself instead of using its stored energy for your buds
70-80f (without co2) and a 10-15 degree night drop @ temps 60-70 is the perfect conditions for your babies
also some growers match the temperature of the soil with the water they use, this helps from shocking the plant.
soil should always stay 60-70F , a good way to do this is have the intake air run by the pot. The temp usually is higher as you go higher in the cab, so making sure your intake is at the bottom will help ensure the right root temps