Auto Sweet Soma -- My first grow!

She's super dense, when I'm in there trying to LST it feels like I'm picking through a salad. I switched her from 24h light to 20/4. She's only had 2 nights of this but she's definitely stretching a lot more which is making the internode spacing larger and LST easier. Some of her biggest/oldest leaves started yellowing at the tips -- pretty sure it's nitrogen deficiency so I upped the level of N and raised pH to 6.3 for the last watering and this seems to be helping.