I would say no, the filter should be on 24hours a day, since turtles spend most of night time in the water I am sure they make more waste during the night then day time.
My favorite things in the world:
1 res, 3 cats, 3 bunnies, 1 dog, 2 african clawed frogs, guppies, pleco, 30+ fancy mice, 2 hermit crabs and 4 small humans