Rust spots on bottom leaves? SLH Auto - Day 40 - RH:65 - T:75 - soil/perlite mix

Your cannabis plant is likely experiencing a potassium deficiency, possibly exacerbated by slight pH imbalances and potential salt build-up. Here's a clear action plan: Adjust your watering pH to 6.5 to optimize nutrient uptake. Perform a soil flush with pH-balanced water to remove any excess salts. Ensure your nutrient mix includes adequate potassium. Monitor the plant for new growth to confirm improvement. By following these steps, you should see an improvement in your plant's health and reduce the yellowing and rust spots on the leaves. Feel free to reach out if you need further assistance

Do you use cal/mag?