any ideas? cal mag or other

the strain is gdp in pro mix. ph is 6.5 and plants have been given maxsea at low constant feeding dosage. i think it is a cal mag issue but idk. the maxsea doesnt have cal mag but my well water does. i didnt have a fan on them for wks and i do think that can mess up calcium intake fan is now on. i did try foliar spraying with cal mag but just yesterday. any ideas or expertise welcome

here is another photo

I don't know about cal mag, it looks just plain hungry. Up the feeding for a few days and see.

ok thanks it was this photo of this plant that makes me think mag

The soil is causing the yellowing, use high Q coco in future. Too much stem is due to the heat, its too hot in there.

the plants have never been hot, cold if anything 55-75f. i have been noticing the problem for about two weeks and i thought it was to do with broad mites or the earth worm castings i mixed into the promix at first but i am kinda puzzled. the promix is heavy with the castings and holding too much water in my view.