Maybe i could drop my 2 cents in for clarity.
Your plants leaves look dark green in the first set of photos - that could be excess nitrogen - but in the next set they look fine - so i'm guessing it's the photo thats making them look dark green.
Adding heat will only increase transpiration. That in turn should increase uptake across the board. (but obviously keeping within acceptable heat parameters (non CO2 enriched) of 70-85f)
Too high EC, PPM, TDS or "nute strength" will cause tip burn first so if you have burning leaf tips - you've gone in to hard and need to back of the nutes a little bit.
Hope this helps
Blue ^_^
Edit: And i would not personally worry about a bendy branch and the plants look nice and healthy