White Clumps In Roots (DWC), Plant Drooping/Dying

I have one gigantic plant in a DWC, all the plants around it are doing excellent but this one, the bottom parts (it's all side lighting so not due to low light) are drooping hard core, it actually looks like a plant does when the DWC bucket is empty and it begins to die. There are a ton of little white clumps floating with the roots inside the bucket, as you can see by the pictures. I'm two weeks from harvest, and about a quarter of this plant is already dead. Need solutions now!
I have no fear of going hardcore on this girl, if I need to use bleach or motor oil and there's some assurance it'll work, fuck it I'll use it. Not really looking for the be-gentle approach because if I don't solve this issue ASAP this plant is gunna be D-E-D DEAD. I should add the stored container smells a little funky.

I just got rid (I hope) of something similar. I removed the plant and gave her a thorough rinse, then soaked her in a somewhat strong mix of HydroSparkle (H2O2 will do). Another rinse and another soak.

Bucket, hoses and air-stones, I soaked (20 minutes) and scrubbed in a very strong bleach solution.

She's back in the bucket with just Ph balanced water for a couple of days, then new water and 1/2 strength nutes.

So far so good.

Good luck.

It's not a remotely modular grow, it's a vertical screen of green, so I'll have to try similar using a siphon, ie siphon once, fill with h2O2 solute, etc.. What kind of concentration of h2o2 should I use, that is, how much and at what strength? I'm a less-is-more type, never really used h2O2.

5% solution should do the trick.

the clumps could be nutes, i once had some standard house plant feed lying around and used that, it settled in clumps similar to yours.

the bad smell suggests the start of rot but roots look healthy.

how much air do you have going into that bucket.

can we see the plant?

good luck draining and filling is a cnut when you cant move the buckets!!!

Have you considered trying this with your grow???

https://www.rollitup.org/dwc-bubbleponics/361430-dwc-root-slime-cure-aka.html