I have a data logger that creates a spreadsheet. In one of the fields is the
date and time in 10 min increments, the other field is the pump output. I
want to be able to do two things.

First is add all of the pump output from say 9am to 9pm on a given day
Second, I want to be able to add all of the pump output for a given day.

I need to do this calcuation hundreds of time, so I am hoping there is a
sumif that will work, I just cannot seem to make it work.

thanks