There seems to be a big debate over whether or not a hydrogen peroxide dunk (h2o2) works in the removal of root rot and long story short, it worked for me.
The best way to remove it is to detect it early before it spreads and contaminates everything.
You can use hydroguard, which I was doing, but if you do not have a good way of keeping temperatures low in your water(around 65-67 degrees), you will likely suffer my same fate.
This is my first hydro grow and I went through a lot, but you could learn how I addressed my issues.
I started with hydroguard, but after this experience, I converted to a sterile grow, swapping out hydroguard with hydrogen peroxide and now my plants are thriving.