That's a classic early flower transition issue with autos — they can be finicky about nutrient balance during that switch. Your EC and pH are in good ranges, so you're on the right track there.
Given that you're seeing burnt tips when pushing EC higher, it's likely more about nutrient ratios than overall strength. Fast Buds genetics tend to be pretty nutrient-sensitive, especially the Cheese line. The lower leaf yellowing during early flower is often nitrogen being pulled upward as the plant redirects energy to bud development.
With Shogun nutes, you might want to check if you're running their full bloom transition schedule — sometimes backing off nitrogen slightly while maintaining or slightly increasing phosphorus and potassium helps. The mag deficiency possibility is worth exploring too, especially in coco which can lock out magnesium.
A few things to consider:
- Cal-mag supplement if you're not already using one
- Check your runoff EC to see if you're getting salt buildup
- Maybe try splitting your daily feed into two smaller feeds to improve uptake
The 10-20% runoff is perfect for coco. Since you caught it early, you should be able to dial it in before it spreads too much.
Alex
