Green roots but no algae...?

I am in the first week of flowering, had minor ph problems which I corrected, there is no algae build up if any at all. I just got in today and a few larger strands of my roots are a blueish green color but they weren't like that yesterday when I pulled them to clean everything and change my water. Could it be light exposure just from transferring them to the holding tank? My reservoir for my bubbler is completely dark, using distilled water and with nutes ph is at 5.4.