My girls had a bad case of root rot due to my temps getting to warm. I rinsed the roots, carefully taking the slime off, and used Hydrogen Peroxide (Walmart).
I had two DWC's going at the time, and in one I added nutrients back immediately, the other I added back at 1/2 strength. I did this because I wasnt sure what to do and got conflicting info.
the one I used 1/2 strength came back quickly. The ones I used full strength nutes on almost died.
Just my personal experiment, but thought I would pass along.
Glad I didnt kill them off like some peeps said to do. they came back healthy and gave me good smoke.