Willycox420 based on your photo's here are my three guesses on the issue -

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PH Fluctuation

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Magnesium Deficiency

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Potassium Deficiency

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How to Remedy the situation: (as long as you're NOT using living soil)
  • Flush the growing medium with 3x the amount of ph balanced water (5 gallon bag = 15 gallons of water) The first 5 gallons mix with1 small 8-10 oz bottle of over the counter hydrogen peroxide. Take your time and allow the water to fully saturate the growing medium. This will reset the nutrient levels in your growing medium.
  • Allow your growing medium to dry to the first or second knuckle on your index finger
  • Your first feeding should be at half nutrient strength
  • Remove all but a few of the damaged leaves for comparison and watch to insure the issue does not get worse and/or spread to other leaves