I've been using the CAP Ebb & Grow, and have been using the House and Garden line of nutes. The very expenseive products have natural enzymes that break down and eliminate root rot. They also require that you do NOT add oxygen to your res, as it negativally affects the root excelator, which is $75 for a very small bottle, yes, its shocking, but its the best. It also has drip clean, which natuarally breaks down and eliminates salt build up.
At the end of a grow, my roots are white and happy, and my nugs are sick. I'm a big believer in the concept of you get what you pay for.