COCO COIR Problems in flowering

[Chrisjames47]

Hello people, I am nearly 8 weeks since 12/12 flip and nearly 7 weeks flowering. I tested my runoff ec yesterday and it was 2.0 ec when the feed I'm putting in is only 1.2 ec do you think I should lower the feed strength also the buds stopped developing after week 5 so do you think they will eventually swell up? And what do you think these black marks are on some of my leaves? I will post some pics.
Any inputs will be appreciated. Thanks

 

[Rwise]

Whats the PH? Looks to be acidic from here, but its only a picture not a test.