Funguns?! or normal? Deep Water culture + Top Feed

Woody/corky at the bottom.. no fuzz or mush/slime? then all is fine. Low S could cause a corky stem at bottom. Some trace element deficiencies can cause it too. I am fairly certain older plants display this sort of property over time, too. Low s would have other ver obvious symptoms, so it's easy to rule out -- purple streaks in stems, chlorosis in new growth but yellowing from petiole-and-out, not tip-and-in. Highly unlikely it is trace element issue with hydro nutes, so i don't think this is anything to be concerned about. the lower portion are just airpruned roots -- there is a fancy vocabulary for it but i'm brain farting. It's from moisture so the cells start to differentiate into the start of some roots (no different than the nodular start for a roots on a clone) ... but then it's hit by light and it doesn't develop further. they are no concern. probably inevitable in your dwc setup. "adventitious roots" i think is the proper name for them.