Plant leaves droop ebb & flood is this normal?

hi my question is my plants seem to droop a little bit before lights out , they seem to be fine all day just near the end of the night,i water 1 time a day in ebb & flood,does the drooping mean i should water again.Has this happen to anyone growing in ebb & flood? Thanx for the advice in advance.

I've had that in soil. I'm still pretty new and don't really know what it means but there you are...