we also gave them seaweed mix... but we think it was the calmag that really helped. we overwatered our coco, a no no, it lost its calcium and magnesium buffer. bad move.
hey man, we had same problem, same plants, same ph. feed them some calmag in low doses. if your using coco let them dry out a bit in between. it will help, also remove some of those pointless little branches you get with ak.
good luck