Are these girls dying

Second run at rdwc, the Plants have no life in them. They are droopy and some of the leaves are crispy at the tip. We are having a few freezing cold days here at the moment so I put in an oil radiator which I've noticed has now caused the humidity to be down at 30%. I also changed my res two days ago the water was pretty cold going in and took a couple of hours to heat up. Is this due to low humidity or am I overlooking something else