Rusty spots mid-top of plants. A couple on each plant. Thoughts?

Lower pH darker the leafs. Add few drops of fresh lemon juice to the water. Your in bud so have to check the strain too. Some strains pull nuits out of the leaves and shed them or turn yellow, blue, purple.

I would say yes to the calcium,magnesium. I would also say only go to 6.5. I will end with it's not a lockout it's an air movement issue. 👍👍 From The White House.

Hey :-) Don't let the Ph go up at soil between 6.0 and 6.3 :-) :-) If you overfeeded, I would do the following ;-) If you overfeed, I would proceed as follows. Best if you have osmosis water and mix the stale water for 24 hours (after 24 hours the chlorine has evaporated somewhat) to an Ec value of 0.2. Then add Cal / Mag until the Ec is 0.4. This is your source of water, so you can flush. At the next pour, start with a quarter of the feed dose.