Scratch that I just read back and you listed your water temps at 65 so you must have been using a chiller. Why do you think you kept getting rot did you ever figure that out?
It was winter, and I regulated cold outside air to keep the water cool.
I have a theory about that hydro system. I don't think there was anything wrong with it. I had just started using dyna-zyme in it around that time. I don't recommend it in hydro at all. The dead matter and the enzymes themselves all die, turn brown, and look exactly like root rot. I even tried sterile rez with chlorine, but on the same plants. I think I was prejudging the root rot on the roots before I saw it on the plant. I kept scrapping grows because I didn't want to have a problem in flower, so kept trying to solve it in veg.
I got tired of chasing it, and after that many grows without a harvest I pulled the whole system in one night. About a month ago I was thinking about it, and that is how I came up with the zyme theory, lol.