I do not know what is causing this. They are in the third week of flowering presently.
The system is Top feed Hydroponic using General Hydroponics Products, RO water.
The second to last feed was; 1.5 tsp/gal Micro , 1 tsp/gal Bloom, 1tsp/gal Cal/Mag, and 1/2 tsp Big Bud. PPM was 920...