Slight Leaf Discoloration. Early zinc deficiency?

Your soil pH is likely to high for your plant to correctly absorb magnesium, which is the deficiency showing on your picture. I’d personally drop the feeding solution pH to around 5.5 and water until I get about 20% runoff for a few weeks in order to bring that medium pH down. It’s actually an issue I often encounter when growing with new coco/peat/perlite medium but it always self resolves in the end providing you prevent salt buildups by watering until runoff at a lower pH. Good luck!