Overfertilization? What could it be?

If the issue is related to one of two growing mediums only. maybe that's the problem. and maybe its not a overfeed but an under. typically when the lower leaves of the plant yellow and work its way up. that's a nitrogen deficiency. but not always. The burning does look like overfeeding a bit, but I feel that's seen on green leaves not yellow ones and more then just the lower ones. Id test your PH of the two different medium types and see if that could be an issue, Maybe one brand of the medium has shifted a bit more then the other causing lockout. Can test by taking a small sample of soil. tea spoon or tablespoon from a lower depth in the pot. Soak it in distilled water and stir it around. use PH pen 15 min later till it levels out on the reading. Could also measure the PH run off if their is any and see how much it varies between the two mediums then adjust from their. Best of luck

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