Yeah, lets first get the specs on what your plants are getting, so we know how to help you correct it. Also, give us some decent pics of the plants, the roots and your system. I dove into DWC/RDWC at the beginning of the year - and despite my previous hydro experience as well as a solid science background - my entire system got root rot. 8, 5 gallon buckets - then even my EZ Cloner - everything. I battled it for quite a while - lost 2 of the plants and successfully flowered 6 of them.
I'll tell you how I handled it, and why - as well as the realistic pro's and con's and help you weigh what your next step is.
How big, or how old are the plants - and if you needed to scrap them and start fresh, do you have that option? Also, rooting plugs like rockwool or rapid rooters are often the source, if they are too low in the netpot, staying too wet - just putting it out there.
Here's the thing... It's costing resources while these plants are stalled. Water, nutes, power and your hard work are being spent to keep them from declining. It's likely going to take a few weeks to get them back on track and they'll take a beating getting themselves sorted out. In the end, I spent FAR more in resources than I would have if I had started over. In fact, when my plants had finally started growing well again (they were large) I had placed a 3 week old clone in with them and flipped them all at the same time - and the clone pretty much caught up with the ones that I spent a month working on.
Mine were in pretty tough shape. The plants were about 6 weeks old, and pretty large, when the problems started. They were in 5 gallon buckets at the time and I didn't know that I either needed to employ a disinfectant or a beneficial like Hydroguard. I first cut away all dead and dying root material. Anything that pulls away. Then I soaked them with a kitchen sink sprayer and sprayed off everything I could, thoroughly soaking through the netpot. I moved them into the Under Current RDWC, where I had planned to flower them. Here at least I could treat all 6 plants at once instead of dealing with buckets.
To get them to grow roots again, they can't take up nutrients, so they cannibalize themselves, turning yellow as the sugars are sent to build new roots. This is where they'll take a beating.
- Run the plants for a good 4 or 5 days with RO water (or tap if that's what you use) along with a rooting stimulator like Rhizotonic as well as an enzyme to break down the dead matter remaining - like Cannazyme - and I'd highly recommend a chlorine disinfectant like UC Roots. You just mix it to direction and you can't go wrong. If you decide to do beneficials, I'd say switch over after you get this shit killed. Run it like this with the level as high as your plants can take it. I run mine 2" above the base of the netpot - but I don't use rooting plugs. You want the roots all the way up to be bathed in this stuff.
- When you see roots coming out, reintroduce 1/4 nutes for a week. The plants will get all sorts of banged up with deficiencies - but now they have roots to get what they need. Go back up slow.
But let's back up and find out what happened so we can work that in and get it figured out. Sorry you're going through this, but I feel your pain...