Northern Lights Auto- First Grow

Beginning of week 3! Not sure if yellowing is mag deficiency, her getting used to the hot soil, or a combo. Or neither lol but she’s steadily growing. Thinking by the end of this week or early next week I’ll need to start giving nutes. Thinking of starting LST soon. 4/4- Rust spots, slight curling up at edges of bottom leaves, slight wilt. Believing the cause is overwatering, so cutting water given in half and lowering frequency of watering. “Hot” soil as well, thinking if nutes will need to be given, it’ll be in flowering. Flushed it with plain distilled water and it brought soil up to around 6 pH from pH of around 5.5.