Any problems turning off return pump but Powerheads left on

[Basterb]

I'm wanting some quiet time in the evenings to watch a movie. Is there any harm turning the return pump off. Left in the sump is the skimmer, refrugum and heater. I can't see the water cooling off that quick in 2 hrs

But keeping the powerheads on in the main tank. Any problems? I could probally keep a heater in the overflow if it's an issue.