you said about spraying well when they were about 2 weeks into bloom i got an infestation of the dreaded spider mite. i did hit them hard with the spray but, it did the job and wiped the out. it was several days after this treatment that this problem strated to manifest.
they have been on 12/12 for 4 week 5 days, the plants are 7/8 weeks old from taking cutting.
i test my ph with a digital tester and it has just been recalibrated last week.
the coco balls are clay/terracotta balls, they are in there just to give abit ov space for airation of the roots and soil.
the clay balls,2 part vitalink and 6.5 ph is something i use always and up until now have never really come across any major problems.