Brown tip leaves and red in stem

My plants on third day of flowering and I noticed the tips are turning brown and curling down along with some red lines in the stems? My pH level has been riding High but yet my phosphorus and potassium levels are low any suggestions? I'm using fox farms bag dirt(bat guano couple different bone meal) and I had to lay off the nutes(fox farms big bloom liquid feed) I was gettin nute burn.. im using the same soil in all 3 of my females one of em seems be maybe even be "stretching" I'm more worried bout the one flowering I need some opinions plz

An upclose of the tips & stem would help here.

But your plants look fine. Mine has dark red stems on the fan leaves probly genetics.
Check your light intensity for the tips