Help asap plz....!

ok fellow grower I'm a little ways into veg I just switched soils from roots organic origanal and transplanted into pro mix bx and I'm just wondering is there any type of extra supplements I need to add to my water to make my plants happy as possible because lately after transplanting into the pro mix bx I've notice these little brown spots on my bigger fans leaves with now is spreading to my smaller leaves I personally believe it's a cal/mag issue but any expert advice would be great pics below... Using flora series complete line up of nutrients and water with a ph between 6.0 and 6.5 never higher

Calcium and magnesium. The nutes have some but not enough. Are you using all 3 as directed on the label when you feed? A Tums dissolved in boiling water and blended added to a tablespoon Epsom salts in a gallon of water is a good start. Don't worry about the free floating particles from the Tums unless they are in chunks. The acidity of the medium will time release those smaller pieces.

Ok cool I may give that a try my next watering and yea I'm using the all 3 of the flora series I also have a bottle of cal/mag sitting around would I be able to just use that