im having a few plants in early bloom that appear to have their pistils burning and dying. its not affecting the whole plant just certain buds. not even the ones closest to the light. alittle background: i grow in promix bx 15 gall pots. 2 under each 1000 watt hps. 10000 watt total in perpetual. got great air movement across the plants. temps 73-82 humidity 40-55. i use ionic line nutes. mighty wash spray every couple weeks. done nothing different for past couple years. any ideas guys?