Seedleranswered grow question a year ago hello! if it's slimy and the roots feel mushy then its root rot but could also be colored fertilizer or dust from the claypebbles u maybe forgot to wash.
if it's root rot make sure that
a: pump is ALWAYS!!!!!!! on, bubbles need to be there all the time.
b: water temperature is really important. above 25Celcius water temperature there will be root rot. optimal temp is around 23Celcius because there is the biggest amount of oxygen for the roots.
c: water level should be high enough so the roots hit the water, the little netcup should NOT touch the water.
d: (probably not but) bad bacteria from too much light coming in or something else. you can drop in some hydrogen peroxide to clean the tank, no hydroguard or something else is needed, if you keep a, b and c in check.
i hope this helps! i had also problems with my first DWC grow, u can look at it, how i fixed it and how it looked.
Happy growing my friend (: