Early Girl you have done a good i would be proud to get buds like that, but maybe something is not rite with your nutes, but also 1200 watts of HPS for 12 plants how are your temps?
Do you have a fan on your plants. Maybe hot spots from lack of air flow? Seems like if was a problem with nutes it would affect the whole plant. You should have some type of upward airflow to push the cool air on the floor back up to the top of the room.