What are recommended best practices for maintaining a closed loop at peak performance? Rust inhibitor? Checking PH? How often? Should a complete change of fluid be done? If so, approximately how often? Any other additives that are recommended? I just started system up in December of '18 so it is not an issue yet, but want to be prepared. I am using ethanol antifreeze, but also for others benefit, post any difference with other types as well. Your advice would be appreciated!