Hey, u have many options when it comes to keeping a healthy root system as there is not substitute for preventative measures. It is important to clean ur res every 1-2 weeks when changing solution.
Res Cleaning Product-HTH Shock-N-Swim
brown slime algae(Cyanobacteria)-USE *IN RES---SM-90, Zone
Also root can be sprayed with 3% H2O2, next use 30% H2O2 in ur solution
These are a few options u may implement...I like the proactive approach to try to avoid the problem from the start.