Heres what we did. Removed, gently, some soil from the top half inch or so.
Then put a fresh layer of soil down and ran over a gallon of tap water thru them and let it drain. The tap sat out overnight to get rid of some chlorine. Put them back in tent. Neville looked liked is was suffering less but light green. The COB'S could be bleaching it some so i dialed back the intensity a bit. Light at 22 inches.