Wish I had enough knowledge to help you but I think once the rot set and get a hold of the root system for real you cannot heal the plants back to health, have to be on it in time and brew lot´s of tea. Same happen to me, got myself a chiller and could not get rid of it just came back again and again almost tore my hair off. Had to clean everything, sterilize very carefully and use tea from the start before it finally worked. Sterilize everything like crazy and start over, that is what I did including grow space, gear, all of it. I think sometimes it´s faster to just start all over cause decease free healthy strong plants grow so fast. But better someone with more knowledge like Heisenberg answer that for you, I would pull, sterilize and start over but like I said wait for a better answer before you decide what to do? Good luck.