Brown Spots on leaves

High Sugahmama, Yes you are 100% right, this is caused by a magnesium deficiency. The cause of this deficiency could be underfeeding or overfeeding. And I do think that the problem in this case is a nutrient lockout due overfeeding. But it doesn't really matter you can fix both of these problems with a good flush of your soil and I will explain you how you can do that the best. You can do this flushing by slowly pour water pH 6.2 onto the top of the soil, allowing it to drain freely from the bottom of the pot. Pour slowly, so the water doesn't overflow from the top of the pot. Use approximately four times the pot's volume in water to flush the soil. For example, use 1 gallon of water for a 1 quart pot. After the flushing you need to let the soil (almost) dry out completely. When you did this just start giving nutrients with pH 6.2 and EC 1.2. From then just keep the pH 6.2 during your whole grow and up the EC with + EC 0.1 every week till you reached EC 1.8 (do not give more then EC 1.8) and just keep giving EC 1.8 till harvest. Happy Growing! 😋