I ran about 10 DWC buckets for years and never had problems with root rot even when temps got a little high. I used sodium hypochlorite aka Clorox Bleach. Easy peasy. People use all kinds of products and many have issues. Household bleach or pool shock aka calcium hypochlorite if you're worried about the small amount of sodium in bleach and you shouldn't have any issues keeping things in check.
You might think about a different growing method. Coco is less hassle and just as good as far as plant growth as DWC. I'll never bother with the hassle of DWC again. I still have all my net pots and most of the buckets and I can't give them away. If someone asked me which way they should grow DWC would be on the reject list. It can be done but it's not worth the hassle. That's just my opinion and many are extremely successful with DWC. I was but coco is just as good.
My net pots are just taking up space these days.
