Small brown speckled spots on leaf of otherwise healthy plant?

@Organoman: At about 2 weeks in flower, I only just started the 'transition feed' which starts moving the balance from nitrogen over to the P/K side of things but still has a really good healthy amount of nitrogen still in it. @AsNoriu: The lights are maintaining the proper PPFD/DLI for the plants...these spots are mid-plant and the stuff up top is just fine. Probably right on the overfeeding by a little though. My feed/water pH is always 6.5 and I always go to 20% or more runoff to stay out of a lockout situation. Cal/mag is a good question...I have some but I'm not using it. My water is unsoftened well water with a native PPM of 221, I've always been under the belief that it should be enough calcium? Not to terribly focused on it in terms of stress, but I'd like to stop problems early if I can. Their next watering should be still a few days away, so I have some days to see what develops.

And stop nitrogen, I can see even toxicity appearing, leaves curling in and very dark green. Think @Organoman missed your diary, he is right in general, just not in your case, you overfed girls a bit ;)

To me it's first sighns of led burning your leaves, use minimal amount of calmag with good pH on clear waterings , no feed, just water and 0.5 ml/l calmag. Follow good watering regime and pH. Such leaves will appear anyways, plant sometimes decided to utilize some of his parts and move nutes or unshade some part, so don't stress, but if it will start to spread, keep an eye on drinking pattern, it usually changes a lot and people built problems without knowing it. All the Best !!!

So @Doktorholland, maybe potassium deficiency? Its early in flower, and I've just started to transition to using a bloom mix of Trio rather than their veg ratios...

dont worry i have this all the time on the leafs in coco just put bloom nutrie

Hmm. It looks a little unusual but I’d say calcium deficiency - could be manifesting for a handful of reasons.. excess Nitrogen locks out calcium if I remember correctly