my coco is buffered form 6-7 ph,you are going in to hight with ph that why it come out at 6.5,try like i say 5.7-5.8 its a must with coco,then form flower on 5.8 -6.3 be just good :Sharing One:

<img src="https://www.autoflower.org/attachment.php?attachmentid=372559"/> Kudo