It would seem like if that the system worked well for 15yrs, and now, all of the sudden the roots are yellow and greasy, that should be a clue.....

and if you have plants that are so stressed as to be mutating, and several folks cant figure it out.....

Something seems to be not as it seems.....How could your friend and advisers do this susccesfully for 15yrs, going thru all the normal ups and downs with all the envrionmental and biological challenges and changes that we all have to deal with, and NOT know about root rot/pythium/overwatering/soil compaction/poor drainage? Peace