Try adding SubCulture to a soil grow, with lots of perlite and good frequent waterings- that would be my choice were I to suffer that problem. Also, Serenade can be added to your res.
Last, the NFT style is an interesting choice for a situation like yours. The constant aeration and washing action over the roots, plus the fact that the water is constantly moving across a filter (you can add extra filtration to help remove dead shit and pathogens), helps prevent buildup of dead cells and rot from setting in.
Hope that helps?
stinkyattic Reviewed by stinkyattic on . Plagued By Root Rot Indoor Grow Method: Hydroponics Medium: Hydroton System: 2 DWC buckets Water Source: Tap Water pH: 5.5 (constant read, calibrated 3 days ago) Tap Water PPM: ~300 Plant Age: 5 week old clone, Day 4 of flower Nutrients: Pure Blend Pro Bloom and Grow (50/50 mix) and Hygrozyme Current PPM: Was 1,000, 750-800 since root rot Rating: 5