How much molasses? How often?
Oh that comment was not directed to you. Sorry about that.
I was being ironic due to a recent thread where molasses was discussed, much in the same way as the unified "calmag deficiency" was mentioned here. Dont ever use molasses in DWC. You can get away with it in coco though. Perfect companion for organic grows if used right.
Molasses will do nothing to neither Calcium or Magnesium deficiency. Sometimes, the phenotype is just a pain to work with. For example, in my current grow of 16 plants, same strain that is usually super stable... yet I have one that is simply a major bitch. Sometimes the spots show up, but not on new growth - it can be a temporary thing. But in your case it does look like a deficiency creeping up.
Strong LED and coco is usually a recipe for calmag deficiency. I will highly recommend brewing a bacterial/compost tea. Not only you will have an army of plant feeders, they will prepare your inputs for better micro nutrient uptake. pH will be higher, around 7 to 7.5, but in this case it is a good thing. Drench your pots and monitor new growth. This will act as a soft-flush, and you can reset and resume the feed again. Don't be scared of removing ugly fan leaves.
Water logging can also show these signs. Are you allowing for a healthy wet-dry cycle, or constantly watering your coco?
