Try his thread and see if it helps....International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!

That looks like too much of something to me rather than not enough of something.
Weedhound Reviewed by Weedhound on . Is this Ca def. or what? This is happening toward the top of the plant. 3 weeks into flower. From what I have read it looks like Ca def. to me, but I am still learning. ;) Rating: 5