at first glance i'd say they are stained from your nutrients. What nutes are you using?

If they smell, are kinda rot looking, or pull off very easy (almost brush away...) then i'd say you are dealing with root rot...

you say the plants are doing ok...that flowering one looks pretty good...so i wouldn't think the roots were bad on her. she looks about 5-6 weeks?

some of the other members may have more insight. i'm still learning myself.

good luck
Skeet
elskeetro Reviewed by elskeetro on . LOOK!!! 0-0 Ok well this is my first real hydro its going alright just i have this set of roots off to the side and there violet red you can see in the pic i thought good roots are white just wondering not showing signs of stress or anything though so ya!!! Rating: 5