SPOTS SUDDENLY

So I have started seeing these dry spots on my plants I have 4 in a 4 x 4 and 3 of them have this on its leaves. Does anyone know what this is and how I can stop its from getting worst. im Using technaflora nutes

Could use a little more info on light and medium, but to take a guess based on look alone, I would ponder calcium deficiency.

Mars hydro TSW 2000
coast of Maine

so even if technaflora has calcium I would still need to give a cal/mag as well?

Mag Sulfate and the heavens will part.

Thank you!