Root rot? and some questions about the cure

This is my first grow, and my first time learning about root rot..


Growth has been stunted on these for a couple of weeks but I didn't know to watch for root rot - if that's what is happening. I went to the store and got some 29% h2o2 and some hygrozyme. I'm wondering whether I should do an h2o2 bath and rinse and then change the water with fresh nutes and hygrozyme? If I do the bath and rinse what ratio should I use? The one plant looks like I might lose the root ball hanging down, like it would take much to just snap... The other plant doesn't seem near as bad, might I skip the bath and just try the hygrozyme with that one?

I am not an expert. I had a similar situation a few weeks back.

https://www.rollitup.org/hydroponics-aeroponics/708928-root-rot-restart-there-cure.html

I did h2o2 and hygrozyme, followed by beneficials. Plant is growing well, but is weeks behind my other 3 and not nearly as bushy.