you should have cut the lower dieing buds and given that top longer , it looks weeks away from finished imho
whats done is done though sadly
peace
edit, looking at your earlier pics id say (and this is just my opinion because i didnt read what or how you fed them) but i believe the plants are sativa dom and you over fed them causing the lowers and roots to burn , im growing all the same testers and none have done this , i feed half strength of what my indica dom kushes get and i give pure ph'd water every third watering