Is Aeration Necessary for Hydroponics?

Plant roots need oxygen. One of the tasks inside hydroponics is figuring out how to deliver oxygen to the roots while also delivering water and nutrients. A common method to achieve this is to add aeration to the reservoir, thus adding oxygen to the water. We wanted to test if this is necessary in the system we run, so we did a test comparing the output of two hydroponic rail systems: one with aeration and one with no aeration.