[bigeasy]

I would trim off the rot and introduce a bacillus(like hydro guard) but the peroxide will work. Also you fill hydro bucket and the plants drink it down… the root rot will tend to form in that “tide” zone. Try a spray bottle with a solution of bacillus or peroxide and spray the whole root ball enough to wet it often(daily) to keep things a bit more healthy. Pruning the roots will encourage more growth, btw, similar to the growth above.