Yeah, that's what it looks like to me bro. Early stages of calcium def. I would dose with some cal-mag, and that should fix the problem. I keep my Ph around 6-6.3, I just recently had the same issue with one of my 20 some odd strains I have going!
although one that was having problems had (M) mag def, so I just took some good ol' episom salt & added 2 teaspn to a gln of water dosed her with that, aswell as taking some of the mixture & putting into my spray bottle & misting off her leaves aswell. This morning I couldn't see any sign of (M) def at all..
Check them out. Links in the signature, just go to the few last pg's to see them..
let me know what you think... hey! Also, I have a "guessing game" going! I picked a strain & started germing her yesterday, I didn't tell anyone what I picked, that's up to everyone to guess the strain!! I will continue to drop small hints everyday as to what strain I went with. The winner that guesses right will receive (2) FREE gifts from me....
hope 2 see you there..