What to do:
If you think you may have root problems, there are two easy ways to deal with this.
1.) You can purchase Hydrogen Peroxide in 3% - 35% strength.
Mix 1 cup of 3% Hydrogen Peroxide with a gallon of water. For 35% strength Hydrogen Peroxide, mix one tablespoon to a gallon of water.
Water your plants with the mixture to kill any bacteria living in your root area. Unfortunately, hydrogen peroxide also kills good bacteria, which can protect your plant from future infections.
2.) (My prefered method) Conversely, you can start adding
Aquashield to your nutrient-water when you feed.
This will build up colonies of good bacteria that out-compete the bad bacteria and actually promote plant growth.
In addition, the beneficial bacteria will offer protection for those times when the temperature of the grow area rises at a time when you can't control it. When I first got started with bubbleponics, I had a few tough bouts with root rot.
Over the last few years, I've tried many "good bacteria" products including the Great White and Subculture B additives, but no product has ever worked 1/4 as good at maintaining healthy roots as super cheap, readily available Aquashield.