Reason for red / lilac stems of fan leaves?

Some strains normally produce red stems.... but I, too, am growing FastBuds Wedding Cheesecake and do not have the red stems so this is not something associated with this strain. Red stems generally will indicate stress of some kind - if they are lower on the plant but not on top, it's indicating the plant went through something bad earlier in its life.... if they're STILL red on top, then it's something that's going on now. But I don't see anything in your diary that would cause this although I am not familiar with your nutes and it may be there's a little bit too much nitrogen in them as the leaves look pretty dark to me... If the plant is overall healthy, like yours, I wouldn't worry about it much at all.... Just keep an eye out for other problems and jump on them if you see something... Good luck! Very nice grow so far!!