Plants curling and yellowing

[Ashatigerlily]

Hey y’all! So my hydroponic plants have been going through a spell of root rot,brown and slimy roots. My local hydroponic store guy suggested I use root cleaner. After using twice my plants aren’t look to good. I can’t tell if it’s the root cleaner that’s effecting them or if something else is going on?
they are in the 4th week of veg. DWC 5 bucket system. Ph is around 5.7-5.8 and EC is at 2.0 water temp is about 69-70 the hottest
Need advice please! TIA
Picture is of the worst plant

 

[WeedHopper]

Is there light getting to your roots? Usually that's a sign of light leaks or high solution temps. So since your solution temps are below 70 all i can think of is light getting to your roots.
Also did you post this twice because i thought i already seen a thread on this.