Devil Cream First Ever Grow

New week with this girl getting one step closer to harvest! I switched nutes this week from Oldtimer Bloom to Bio-Bizz Grow/Bloom. No reason really, I just didn't like the funky smell of the Oldtimer. Day 42 - When I was checking her out today, I noticed a tinge of yellowing on some of the leaves on the side branches. Does this look like Nutrient burn or Light stress? I don't think it can be light stress as the side branches are much shorter than the main stem, which is more or less okay, so I'm thinking its a nute burn? This might actually make sense, as I think I might have overdone her with the oldtimer last week, maybe she's just sensitive. I'll dial back to plain water for a few feeds I think and see how she responds. Day 47 - She can't support her own weight anymore, so I have to be really careful when I pick her up for watering etc. I'm using a spare hanging hook from my light like a little noose to hold her up straight in the grow space... Looking good though and it smells amazing, beautiful citrus and pine.