dendrobium roots healthy or not-newbie

[Paytyn2flex]

Hello! I am a newbie to growing orchids and I recently was introduced two semi hydroponics. I had a dendrobium planted in it. Went to water it tonight and the bottom of the stems where it meets the clay pellets looked black. so i pulled it out (gently ) and now i remember that it was originally potted in spagnum and i had difficulty get all of it off. My question is, doe the roots look healthy? Is there something I can use to clean them up? Please help. I'll take whatever advice available. Thanks so much