Careful getting your temps too low in the sixties that early in the grow stage. What kind of pots are you using? I use smart pots (fabric pots) and they tend to get a little white mold/powdery mildew around the outside of the pot. Nothing that has caused too many problems for me, but its something that van very easily get out of hand.
I usually drop my temps towards the end of flower, but even with humidity in the 40-50% range the cold temps can invite pm, especially with cold temps that early in the life cycle.