Burning up leaves

I see your already feeding Cal-Mag... And it being a micro strongly leaning towards this not being a case of magnesium deficiency. Are they lower down on the plant getting no light? If this is the case, the plant does this all it's own and is not a bad sign. Have some hydro growing plants that are already abandoning lower foliage. The new grower growth is where we worry about deficiency.

Hello, I'm not sure if I'm seeing this correctly, but it seems like the problem is MAGNESIUM. Without this immobile micronutrient, photosynthesis wouldn't be possible. This mineral is at the heart of the chlorophyll molecule and allows it to absorb light. A magnesium deficiency will give a scorched appearance to the lower growths. The leaves will yellow, dry out, and eventually turn brown. Prevention • Include dolomitic lime in your growing substrate • Use compost rich in manure • Maintain a good pH balance. Solutions • Flush your substrate with water at a pH of 6.0 if it is inadequate. • Epsom salts are a source of magnesium. Add 1–2 teaspoons of Epsom salts to about 4 liters of water and apply until symptoms resolve. I hope this helps you. Don't hesitate to contact me if you need anything, lots of courage!! 😊