Rusty-brown markings coming out on lower leaves.

Opening up a can of worms. Fungal Disease (Rust): Rust is a common fungal disease that can cause rusty brown spots or lesions on leaves. Nutrient Deficiencies: Lack of essential nutrients, particularly potassium, can lead to brown, rust-colored spots on leaf edges or tips. Inconsistent Watering: Allowing plants to dry out too long or overwatering can cause browning, especially on leaf tips and edges. (Not rust) Salt Buildup: Excessive fertilizer or softened water can lead to salt buildup in the soil, causing brown tips. (Not rust though.) Knowing your ph was in 5's is a problem at low ph aluminum will start to break bonds and rapidly replace mainly calcium and magnesium and pottasium bonds. See if you can get your ph closer to 7 maybe 6.7, the lower the ph the lower base saturation of Ca, Mg and K. Cannabis medium will naturally acidify over time, so you gotta keep an eye on her.and not let her drift below 6 ever. Best of luck pal, I'd Give her another week, see how she progresses, let us know 👍.